Technical guide Heat is our element - Buderus

Technical guide 

Logasol solar technology 

for domestic hot water heating 

and central heating backup 

Heat is our element 

Technical guide 

Issue 06/2007

Contents 

Technical guide - Logasol solar technology for domestic hot water heating and central heating backup - 06/2007 

Contents 

1 Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

1.1 Free solar energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

1.2 Energy supplied by solar collector systems in relation to the energy demand . . . . . . . . . . . . . . . . . . . . . 3 

2 Technical description of system components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

2.1 Solar collectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

2.2 Logalux solar cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

2.3 Solar control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

2.4 Logasol KS... complete station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 

2.5 Other system components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 

3 Notes regarding solar heating systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 

3.1 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 

3.2 Regulations and guidelines for designing/engineering a solar collector system . . . . . . . . . . . . . . . . . . . 59 

4 Sample systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 

4.1 Solar heating systems for domestic hot water heating with conventional 

oil/gas fired boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 

4.2 Solar heating systems for DHW heating and central heating backup with 

conventional oil/gas fired boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 

4.3 Solar heating systems for DHW heating with solid fuel-boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 

4.4 Solar heating systems for DHW heating and central heating backup with solid fuel boiler . . . . . . . . . 73 

4.5 Solar heating systems for DHW heating and swimming pool heating with 

conventional oil/gas-fired boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 

4.6 Detailed hydraulic scheme for wall mounted boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 

5 Sizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 

5.1 Sizing principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 

5.2 Sizing the collector array and solar heating cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 

5.3 Space requirements for solar collectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 

5.4 Hydraulic system engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 

5.5 Sizing of the diaphragm expansion vessel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 

6 Design/engineering information regarding the installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 

6.1 Pipework, thermal insulation and collector temperature sensor extension cable . . . . . . . . . . . . . . . . . 118 

6.2 Air vent valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 

6.3 Information regarding the different flat-plate collector installation systems . . . . . . . . . . . . . . . . . . . . 121 

6.4 Flat roof installation for vacuum tube collectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 

6.5 Lightning protection and earth bonding for solar heating systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 

7 Regulations and Directives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 

Questionnaire "Fax inquiry - solar heating system for detached houses and 

two-family homes" (copy template) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 

Keyword index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 

List of abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 

1

1 

Principles 

1 Principles 

1.1 Free solar energy 

The energy that is provided by the sun can be used 

effectively in almost any part of Germany. The annual 

insolation level lies between 900 kWh/m2 and 1200 

kWh/m2 . The "insolation map" gives you an idea of the 

average insolation that can be expected in your 

region(➔ 2/1). 

A thermal solar heating system uses the energy of the 

sun to heat domestic hot water (DHW) and can also be 

used as central heating backup. Solar systems for DHW 

heating are energy-saving and environmentally 

friendly. Combined solar heating systems for DHW 

heating and central heating backup are progressively 

becoming more popular. Frequently it is only 

information about the astounding proportion of 

heating that technically advanced solar heating 

systems can provide today that is lacking. 

A considerable proportion of solar energy can be used 

for heat generation using solar collector systems, 

saving valuable fuel, and fewer emissions reduce the 

burden on the environment. 

2 

Münster 

Frankfurt 

2/1 Average insolation in Germany 

Caption 

1150 to 1200 kWh/m 2 

1100 to 1150 kWh/m 2 

1050 to 1100 kWh/m 2 

1000 to 1050 kWh/m 2 

950 to 1000 kWh/m 2 

900 to 950 kWh/m 2 

Bremen 

Kassel 

Hannover 


Köln 

Freiburg 

Hamburg 

Leipzig 

Nürnberg 

München 

Chemnitz 

Berlin 

Cottbus

1.2 Energy supplied by solar collector systems in relation to the energy demand 

Solar collector systems for DHW heating 

DHW heating is the most obvious application for solar 

collector systems. The regular demand for hot water all 

the year round is a good match for solar energy. 

Almost 100% of the energy demand for DHW heating 

during the summer can be covered by a solar heating 

system (➔ 3/1). Nevertheless, the conventional heating 

system must still be able to cover the DHW demand 

independently of solar heating. Long periods of bad 

weather may occur during which the convenience of 

hot water still has to be assured. 

Solar collector systems for DHW heating and 

central heating backup 

Being environmentally aware means thinking of solar 

collector systems not just for DHW heating but also for 

central heating backup. However, the solar heating 

system can only give off heat if the return temperature 

of the heating system is lower than the temperature of 

the solar collector. Large radiators with low system 

temperatures or underfloor heating systems are 

therefore ideal. 

With an appropriate design the solar heating system 

will cover up to 30% of the annual heating energy that 

is needed for DHW heating and central heating. 

Combined with a back boiler or solid fuel boiler, the 

requirement for fossil fuels can be reduced even further 

during the heating season because renewables such as 

wood can be used. The residual energy is provided by a 

condensing or a low temperature boiler 

Q 

kWh 

1 2 3 4 5 

Caption (➔ 3/1 and 3/2) 

a Energy demand 

b Energy provided by the solar heating system 

MMonth 

Q Heating energy 

Solar energy surplus 

(available for a swimming pool, for example) 

Utilised solar energy 

(solar coverage) 

Energy demand that has not been covered 

(reheating) 


Principles 1 

3/1 Energy provided by a solar collector system in relation to the 

annual energy demand for DHW heating 

Q 

kWh 

6 

M 

7 8 9 10 11 12 

1 2 3 4 5 6 

M 

7 8 9 10 11 12 

3/2 Energy provided by a solar collector system in relation to the 

annual energy demand for DHW and central heating 

a 

b 

a 

b 

3

2 

Technical description of system components 

2 Technical description of system components 

2.1 Solar collectors 

2.1.1 Logasol SKN3.0 flat-plate collector 

Selected features and characteristics 

● Favourable price/performance ratio 

● Consistently high yield through robust, highlyselective 

black chromium coating 

● TÜV-tested connecting technology 

● Rapid collector connection without the need for tools 

● Easy handling because of light weight of 42 kg 

● Meets all federal subsidy requirements in full 

[Germany] 

● Solar fluid has long-term stability due to fan 

absorber with extremely good stagnation 

characteristics 

● Energy-saving manufacture with recyclable 

materials 

● Solar keymark 

4 

R 

8 

4/1 Design of Logasol SKN3.0-s flat-plate collector (portrait) 

V 

7 

M 

R 

Component design and functions (➔ 4/1) 

The casing of the Logasol SKN3.0 solar collector 

consists of a lightweight, extremely strong fibre glass 

frame profile. The back panel is made from 0.6 mm 

aluminium zinc-coated sheet steel. The collector is 

covered with 3.2 mm thick single-pane safety glass. 

The low-ferrous, structured cast glass is coated, is 

highly transparent (92% light transmission) and has 

extremely good load-bearing capability. 

The 55 mm thick mineral wool provides extremely 

good thermal insulation and high efficiency. It is heat 

resistant and non-outgassing. 

The absorber consists of individual strips with a highlyselective 

black chromium coating. The absorber is 

ultrasonically welded to the pipe fan in order to 

provide an extremely good heat transfer. 

The Logasol SKN3.0 has four hose coupling nipples for 

making simple, rapid hydraulic connections. The solar 

hoses can be fitted using spring band clips that require 

no tools. They are designed for temperatures up to 

+170 °C and pressures of up to 6 bar in conjunction 

with the collector. 


6 

5 

4 

3 

2 

V 

1 

R Solar return 

V Solar flow 

M Measuring point (sensor well) 

1 Glass cover 

2 Strip absorber 

3 Pipe fan 

4 Thermal insulation 

5 Back panel of casing 

6 Fibre glass frame profile 

7 Extruded plastic corner 

8 Header pipe cover 

Dimensions and specification 

➔ 5/1 and 5/2

Dimensions and specification for Logasol SKN3.0 flat-plate collectors 

90 

R 

1145 

Technical description of system components 2 

Logasol SKN3.0-s Logasol SKN3.0-w 

V 

M 

R 

2070 

5/1 Dimensions of Logasol SKN3.0-s (portrait) and SKN3.0-w (landscape) flat-plate collectors; dimensions in mm 

V 

90 


V Solar flow 


Logasol flat-plate collector SKN3.0-s SKN3.0-w 

Type of installation portrait landscape 

Gross absorber surface area m 2 

2.37 2.37 

Aperture area (light entry area) m 2 2.26 2.26 

Net absorber surface area m 2 2.23 2.23 

Absorber contents l 0.86 1.25 

Selectivity Level of absorption 

Level of emissions 

Weight kg 41 42 

Efficiency η0 % 77 

Effective heat transfer coefficient k1 

W/(m 

k2 

2 ·K) 

W/(m2 ·K2 3,6810 

) 

0,0173 

Thermal capacity c kJ/(m 2 ·K) 2.96 

Irradiation angle correction factor IAM dir 

τα (50°) 

IAM dfu 

τα 

R 


V 

% 

% 

M 

2070 

95±2 

12±2 

0.911 

0.900 

Nominal flow rate V l/h 50 

Stagnation temperature °C 188 

Max. operating pressure (test pressure) bar 6 

Max. operating temperature °C 120 

Collector yield (minimum yield verification 1) of 525 kWh/(m 2 ·a) for 

BAFA) 

DIN registration number 011-75050 F 

5/2 Specification for Logasol SKN3.0 flat-plate collectors 

1) Minimum yield verification for BAFA (Bundesamt für Wirtschaft and Ausfuhrkontrolle, Eschborn, Germany) in conformity with 

DIN EN 12975 for a fixed coverage of 40%, daily consumption 200 l and location Würzburg 

>525 

R 

1145 

V 

5

2 


2.1.2 Logasol SKS4.0 high performance flat-plate collector 


● High performance flat-plate collector 

● Hermetically sealed with inert gas filling between 

glass and absorber 

● No misting up of inside of the glass 

● Rapid responses 

● Absorber coating permanently protected against 

dust, moisture and airborne pollutants 

● Optimised insulation from the glass cover 

● Powerful full-area absorber with vacuum coating 

and double meander 

● Array connection for up to 5 collectors on one side 

● Extremely good stagnation characteristics 

● Rapid collector connection without the need for tools 

6 

R 

8 

6/1 Design of the Logasol SKN3.0-s flat-plate collector (portrait) 

V 

M 

7 

R 

Component design and functions (➔ 6/1) 

The casing of the Logasol SKS4.0 solar collector consists 

of a lightweight, extremely strong fibre glass frame 

profile. The back panel is made from 0.6 mm 

aluminium zinc-coated sheet steel. The collector is 

covered with 3.2 mm thick single-pane safety glass. 

The low-ferrous, slightly structured cast glass is highly 

transparent (92% light transmission) and has 

extremely good load-bearing capability. 

The 55 mm thick mineral wool insulation provides 

extremely good thermal insulation and high 

efficiency. It is heat resistant and non-outgassing. 

The effective copper surface absorber is provided with 

a highly selective vacuum coating. The double 

meander on the back is ultrasonically welded to the 

absorber to provide an extremely good heat transfer. 


6 

5 

4 

3 

2 

1 

V 


V Solar flow 


1 Glass cover 

2 Full area absorber 

3 Double meander 


5 Back panel of casing 

6 Fibre glass frame profile 

7 Extruded plastic corner 

8 Edge assembly 


➔ 8/1 and 8/2

Inert gas filling 

The inert gas filling (➔ 7/1, item 2) between the 

absorber and the pane of glass reduces heat loss. The 

enclosed space is filled with a heavy, convectioninhibiting 

inert gas as used in thermal glass. The 

hermetically sealed design also protects the absorber 

coating from environmental effects such as moist air, 

dust and pollutants. This gives the equipment a longer 

service life and output is consistently high. 

Double meander absorber 

Because the absorber is designed as a double meander, 

the collector can be easily connected on one side into 

arrays of up to 5 collectors. Connection at alternate 

sides is only required for larger collector arrays to 

provide a homogeneous flow through the collectors. 

The meander design of the absorber makes the 

collector extremely efficient, since the flow is always 

turbulent over the entire flow rate range. The pressure 

drop is also kept low by connecting two meanders in 

parallel. The collective return line of the collector is at 

the bottom so that the hot solar fluid can escape from 

the collector in the event of stagnation. 

St 

St R 

7/2 Design and connection of the Logasol SKS4.0-s double meander absorber 

V 


7 

6 

7/1 Sectional view of the Logasol SKS4.0 high performance 

flat-plate collector with inert gas filling 

Caption (➔ 7/1) 

1 Glass cover 

2 Stainless steel spacer 

3 Inert gas filling 

4 Surface absorber 


6 Bottom panel 

7 Absorber pipe outlet 

Meander 1 

Meander 2 

1 2 3 4 


V 

5 

St 

St R 


up to 5 up to 10 collectors 

7

2 


Dimensions and specification for Logasol SKS4.0 high performance flat-plate collectors 

8/1 Dimensions of Logasol SKS4.0-s (portrait) and SKS4.0-w (landscape) high performance flat-plate collectors; dimensions in mm 

8 

90 

R 

Logasol SKS4.0-s Logasol SKS4.0-w 

1145 

V 

Logasol high performance flat-plate collector SKS4.0-s SKS4.0-w 

Type of installation portrait landscape 

Gross absorber area m 2 2.37 2.37 

Aperture area (light entry area) m 2 


2.1 2.1 

Absorber area (net area) m 2 2.1 2.1 





Efficiency η0 % 85.1 

Effective heat transfer coefficient k1 

W/(m 

k2 

2 ·K) 

W/(m2 ·K2 4.0360 

) 

0.0108 

Thermal capacity c kJ/(m2 ·K) 4.82 

Irradiation angle correction factor IAM dir 

τα (50°) 

IAM dfu 

τα 

Nominal volume flow V l/h 50 


Max. operating pressure bar 10 

Max. operating temperature °C 120 

Collector yield (minimum yield verification 1) of 525 kWh/(m 2 ·a) 

for BAFA) 

M 

R 

2070 

DIN registration number 011-75052 F 

V 

90 


V Solar flow 


8/2 Specification for Logasol SKS4.0 high performance flat-plate collectors 

1) Minimum yield verification for BAFA (Bundesamt für Wirtschaft and Ausfuhrkontrolle, Eschborn) in conformity with DIN EN 12975 with 

fixed cover proportion of 40%, daily consumption 200 l and location Würzburg 

R 

V 

% 

% 

M 

2070 

95±2 

5±2 

0.95 

0.90 

>525 

R 

1145 

V

2.1.3 Vaciosol CPC6 and CPC12 vacuum tube collectors 


● Suitable for sloping or flat roof installation, 

floorstanding installation or facade installation. 

● For heating domestic water and heating water for 

partially solar heating systems and swimming pool 

water 

● High degree of flexibility using collector modules 

with 6 or 12 tubes 

● Excellent design 

● Rapid assembly times due to prefabricated collector 

units and simple, flexible roof and flat room 

installation kits 

● Simple connecting technology for installing several 

collectors next to each other using preinstalled 

threaded connections. No more pipework or 

complex thermal insulation required 

● Solar flow and return can be on the right or left side 

of the collector (optional) 

● Tubes can be replaced without emptying the 

collector circuit - "dry connection" 

● Hydraulic connecting lines easy to connect using 

locking ring screw connections 

● High level of operating safety and long service life 

due to use of high-quality, corrosion resistant 

materials such as thick-walled borosilicate glass, 

copper, aluminium with anticorrosive coating and 

connecting vacuum pipes to solar circuit using "dry 

connections" 

1 2 3 

9 

9/1 Design of the Vaciosol CPC12 vacuum tube collectors 

8 


4 5 

7 

6 

● Tubes are permanently vacuum sealed because all 

connections are glass-to-glass, no glass-to-metal 

transitions 

Energy yield and performance 

● Extremely high energy yield with small collector 

area 

● Circular absorber surface means that each 

individual tube is always properly aligned in 

relation to the sun 

● Extremely high solar coverage rates possible 

● Extremely efficient because of highly-selective 

coated absorbers 

● The vacuum tubes are extremely effective in 

reducing the thermal loss of a solar collector, since 

there is no air in the vacuum that can transport the 

heat of the absorber surface to the glass tubes on the 

outside that are exposed to the weather 

● The heat transfer medium is directly led to the tubes 

without an intermediate heat exchanger in the 

collector 

● The circular absorber always collects direct and 

diffused insolation at different irradiation angles 

● The CPC mirror and direct flow through the vacuum 

tubes make a considerable contribution to the high 

energy yield 

● The vacuum provides the best possible thermal 

insulation, therefore high efficiency also in winter 

and during periods of low irradiation 

1 Flow and return connection 

2 Sensor well 

3 Header tube/distribution tube 


5 Heat exchanger 

6 Vacuum tubes 

7 Heat conducting plate 

8 CPC mirror 

9 U tube 


➔ 11/1 and 11/2 


9

2 


Heat exchanger and heat transfer unit 

The insulated collection and distribution tubes are in 

the heat exchanger (➔ 9/1, item 5). 

The flow and return connections can be on the left or 

right side (optional). 

Each vacuum tube contains a U-tube with direct flow 

that is connected to the collection or distribution tube 

in such a way that each individual vacuum tube has 

identical hydraulic resistance. This U-tube is pressed 

onto the inside of the vacuum tubes with the heat 

conducting plate. 

Vacuum tubes 

The vacuum tube is a product with optimised geometry 

and performance (➔ 10/1). 

The tubes consist of two concentric glass tubes that 

have a hemispherical closure at one end and are fused 

together at the other end. The space between the tubes 

is evacuated and then hermetically sealed (vacuum 

insulation). 

In order to make solar energy usable, the inner glass 

tube has an environmentally friendly highly-selective 

coating on the outside and is therefore designed to be 

an absorber. This coating is therefore protected in the 

vacuum space. This is an aluminium nitrite sputter 

coating that has extremely low emissions and 

extremely good absorption. 

CPC mirror 

In order to increase the efficiency of the vacuum tubes 

there is a highly-reflective, weather resistant CPC 

mirror behind the vacuum tubes (Compound 

Parabolic Concentrator). The special mirror geometry 

ensures that direct and diffused sunlight falls on the 

absorber, even at unfavourable irradiation angles 

(➔ 10/2). This improves the energy yield of a solar 

collector considerably. 

10 

10/1 Sectional diagram of a vacuum tube in the Vaciosol CPC6 and 

CPC12 vacuum tube collectors 


1 Copper pipe 

2 Heat conducting plate 

3 Absorber layer 

4 Vacuum tubes 

5 CPC mirror 

10/2 CPC mirror of the Vaciosol CPC6 and CPC12 vacuum tube 

collectors 


5 

4 

3 

1 

2


Dimensions and specifications of the Vaciosol CPC6 and CPC12 vacuum tube collectors 

101 

Vaciosol CPC6 Vaciosol CPC12 

2057 

11/1 Dimensions of the Vaciosol CPC6 and CPC12 vacuum tube collectors; dimensions in mm 

Vacuum tube collector, Vaciosol CPC6 CPC12 

Number of vacuum tubes 6 12 

Type of installation vertical 

Gross absorber surface area m 2 1.43 2.82 

Aperture area (light entry area) m 2 

1.28 2.56 





Efficiency η0 % 66.5 

Effective heat transition coefficient k1 

W/(m 

k2 

2 ·K) 

W/(m 2 ·K 2 0.721 

) 

0.006 

Thermal capacity c kJ/(m2 ·K) 7.974 

Nominal flow rate V l/h 46 92 


Max. operating pressure bar 10 

Collector yield (minimum yield verification 1) of 525 kWh/(m 2 ·a) 

for BAFA) 

702 

EC type test Z-DDK-MUC-04-100029919-005 

11/2 Specifications of the Vaciosol CPC6 and CPC12 vacuum tube collectors 

1) Minimum yield verification for BAFA (Bundesamt für Wirtschaft and Ausfuhrkontrolle, Eschborn, Germany) in conformity with 

DIN EN 12975 with fixed coverage of 40%, daily consumption of 200 l and location Würzburg 

101 


2057 

% 

% 

1390 

>95 

525 

11

2 


2.2 Logalux solar cylinder 

2.2.1 Logalux SM… dual-mode cylinder for DHW heating 


● Dual-mode cylinder with two smooth tube indirect 

coils 

● Available with blue or white casing 

● Buderus thermoglazing and magnesium anode for 

corrosion protection 

● Large cleaning aperture 

● Low heat loss due to high-grate thermal insulation 

● CFC-free insulating casing made from 50 mm thick 

rigid polyurethane foam (Logalux SM300) or 100 mm 

thick flexible polyurethane foam (Logalux SM400 and 

SM500) 

Design and function 

Different cylinders can be used, subject to the 

individual application and system capacity. The 

Logalux SM300, SM400 and SM500 dual-mode 

cylinders are designed for solar DHW heating. 

Conventional reheating by a boiler is an option. 

The large size of the solar indirect coils inside the 

Logalux SM300, SM400 and SM500 dual-mode 

cylinders provide an extremely good heat transfer and 

therefore create a high temperature differential in the 

solar circuit between the flow and the return. 

A further indirect coil is fitted into the upper part of the 

cylinder to ensure that hot water is always available, 

even if little insolation is available. This indirect coil 

can also be used for reheating using a conventional 

boiler. 

The mono-mode Logalux SU... cylinder can be used in 

existing heating systems. Another technical solution 

provided by Buderus is a cylinder primary system 

consisting of an SU400, SU500, SU750 or SU1000 

mono-mode cylinder with a fitted plate-type heat 

exchanger (Logalux LAP heat exchanger kit ➔ Current 

technical guide "DHW cylinder"). The Logalux LAP 

heat exchanger kit can be used for reheating with a 

conventional boiler. Wall mounted or floorstanding 

gas/oil fired boilers and solid fuel boilers or a 

combination of the above are generally suitable for 

reheating. 

12 

12/1 Components of the Logalux SM300, SM400 and SM500 

dual-mode cylinders 

Caption 

1 Magnesium anode 

2 Thermal insulation (rigid foam insulation for Logalux SM300, 

flexible foam insulation for Logalux SM400 and SM500) 

3 DHW outlet 

4 Cylinder 

5 Upper indirect coil for reheating with a conventional boiler 

6 Solar indirect coil 

7 Cold water inlet 

Dimensions, connections and specification➔ 13/1 and 13/2 


1 

2 

3 

4 

5 

6 

7

Dimensions and specifications of Logalux SM... dual-mode solar cylinder 

13/1 Dimensions and connections of Logalux SM... dual-mode cylinders 


Logalux dual-mode cylinder SM300 SM400 SM500 

Cylinder diameter with/without insulation ØD/ØD Sp mm 672/– 850/650 850/650 

Height H mm 1465 1550 1850 

Cold water inlet / drain H EK/EL mm 60 148 148 

Cylinder return on the solar side H RS1 mm 297 303 303 

Cylinder flow on the solar side H VS1 mm 682 690 840 

Cylinder return H RS2 mm 842 790 940 

Cylinder flow H VS2 mm 1077 1103 1253 

DHW circulation inlet H EZ mm 762 912 1062 

DHW outlet ØAW 

HAW Feet centres A1 

A2 

inch 

mm 

mm 

mm 

R1 

1326 

400 

408 

R14 

1343 

480 

420 


R14 

1643 

480 

420 

Cylinder capacity total/standby l 290/≈130 390/≈165 490/≈215 

Content, solar indirect coil l 8 9.5 13.2 

Size of solar indirect coil m 2 1.2 1.3 1.8 

Standby heat loss 1) 

ØD 

ØD Sp 

Performance factor (upper indirect coil) 2) 

Continuous output (upper indirect coil) with 

80/45/10 °C 3) 

AW 

VS2 

R 1 

EZ 

R 3/4 

RS2 

R 1 

VS1 

R 1 

RS1 

R 1 

EK/EL 

R 1 1/4 

M1 Ø19 mm internal 

M2 Ø19 mm internal 

kWh/24h 2.1 2.81 3.3 

N L 2.9 4.1 6.7 

kW (l/h) 34.3 (843) 34.3 (843) 34.3 (843) 

Number of collectors ➔ 83/2, 86/2 ➔ 83/2, 86/2 ➔ 83/2, 86/2 

Weight (net) kg 144 202 248 

Max. operating pressure heating water/DHW bar 25/10 

H 

H AW 

H VS2 

H EZ 

H RS2 

H VS1 

H RS1 

H EK/EL 

20 – 25 

Max. operating temperature heating water/DHW °C 160/95 

13/2 Specification of the Logalux SM300, SM400 and SM500 dual-mode cylinders 

1) In accordance with DIN 4753-8: DHW temperature 65 °C, ambient temperature 20 °C 

2) In accordance with DIN 4708 when heating to a cylinder temperature of 60 °C with a heating water flow temperature of 80 °C 

3) Heating water flow temperature/DHW outlet temperature/cold water inlet temperature 

A2 

Plan view 

A1 

13

2 


2.2.2 Thermosiphon cylinder Logalux SL… for DHW heating 


● Patented heating lance for stratified cylinder 

heating in the respective highest temperature zone 

● Buoyancy-controlled plastic gravity flaps for 

stratification system 

● DHW available extremely quickly via the solar 

heating system and less frequent reheating using 

the boiler 

● Buderus thermoglazing and magnesium anode for 

corrosion protection 

● CFC-free insulation casing made from flexible 

polyurethane foam, 100 mm thick at the sides and 

150 mm thick on top (removable) 


Buderus provides thermosiphon cylinders in various 

shapes and sizes for DHW heating. All versions are 

based on the thermosiphon principle (➔ page 15). 

The solar indirect coil only heats a relatively small 

quantity of DHW, almost to the solar flow 

temperature. The heated DHW rises directly upwards 

into the standby reservoir through the heating lance 

(item 6 ➔ 14/1). With normal insolation, the set 

temperature is soon reached. Reheating using a 

conventional boiler is therefore less frequently 

required. 

Depending on the solar heating, the DHW only rises 

upwards until it reaches the layer with the same 

temperature level. Then the relevant buoyancycontrolled 

gravity flaps open (item 7 ➔ 14/1). The 

cylinder heats itself in this way layer by layer from top 

to bottom (➔ page 15). 

Particularly with a control unit that is suitable for 

double match flow operation (SC20, SC40, solar 

function module FM443 or SM10), this principle is 

optimally coordinated by the flow rate adjustment of 

the variable speed pump and the heating of the 

standby reservoir with higher priority. 

Mono-mode cylinder Logalux SL300-1 

The upper indirect coil for reheating by a conventional 

boiler is not fitted to the Logalux SL300-1 mono-mode 

cylinder with 300 litre capacity. The cylinder is suitable 

for retrofitting an existing DHW system by adding a 

solar heating system. 

14 

Dual-mode cylinder Logalux SL300/400/500-2 

The dual-mode solar cylinders SL…-2 with capacities of 

300 l, 400 l and 500 l have a solar indirect coil and an 

upper indirect coil for conventional reheating. These 

cylinders are also available with white casing as 

version Logalux SL…-2 W. 

14/1 Design of the Logalux SL300-2 thermosiphon cylinder 

Caption 



3 DHW outlet 

4 Cylinder 

5 Upper indirect coil for reheating by a conventional boiler 

6 Heating lance 

7 Gravity flap 





1 

2 

3 

4 

5 

6 

7 

8 

9

Thermosiphon principle for high levels of insolation 

The heated water rises rapidly and is available in the 

standby reservoir extremely quickly. The cylinder is 

heated up from top to bottom (item 1 ➔ 15/1). 

Because only water from below flows through the 

heating lance at the solar indirect coil, there is always 

AW 1 

V 

R 

15/1 Heating procedure for a thermosiphon cylinder at full insolation 

Thermosiphon principle with low insolation 

For example, if the water is only heated to 30 °C, it only 

rises to the layer at that temperature level. The water 

flows through the open gravity flaps into the cylinder 

and heats the area (item 2 ➔ 15/2). 

The water leaving through the gravity flaps stops the 

water from rising in the heating lance and prevents it 

from mixing with layers at higher temperatures 

(item 3 ➔ 15/2). 

VS 

RS 

Caption (➔ 15/1 and 15/2) 

1 Separating layer between temperature zones 

2 Open gravity flap in heating lance 

3 Closed gravity flap 

AW DHW outlet 

EK Cold water inlet 


V Solar flow 

EK 


AW 

V 

R 

a wide temperature differential between the cylinder 

return and the collector. That ensures a high solar 

yield. 

AW 


V 

R 

EK 

VS 

RS 

1 

AW 

V 

R 

VS 

VS 

40ß C 

40ß C 

RS 

RS 

3 3 

30 30 ßC ßC 

2 2 

EK 

EK 

30ß C 

20ß 20ß CC 

15/2 Hot water leaving the heating lance at low insolation 

EK 

VS 

RS 

1 

40 ßC 

40 ßC 

30 30 ßC ßC 

20 ßC 

3 

3 

2 

2 

15

2 


Dimensions and specification for the Logalux SL… thermosiphon cylinder 

Mg 

M1 

EH 

M2 

M3 

M4 

16/1 Dimensions and connection of the Logalux SL… mono-mode and dual-mode thermosiphon cylinders for HDW heating 

Logalux thermosiphon cylinder SL300-1 SL300-2 SL400-2 SL500-2 

Cylinder diameter with/without insulation ØD/ØD Sp mm 770/570 770/570 850/650 850/650 

Height H mm 1670 1670 1670 1970 

Cold water inlet/drain H EK, EL mm 245 245 230 230 

Cylinder return on the solar side H RS1 mm 100 100 100 100 

Cylinder flow on the solar side H VS1 mm 170 170 170 170 

Cylinder return H RS mm – 886 872 1032 

Cylinder flow H VS mm – 1199 1185 1345 

DHW circulation inlet H EZ mm 1008 1008 994 1154 

DHW outlet ØAW 

H AW 

Immersion heater HEH mm 949 – – 985 

Feet centres A1/A2 mm 380/385 375/435 440/600 440/600 

Cylinder capacity total/standby l 300/≈165 300/≈155 380/≈180 500/≈230 

Content, solar indirect coil l 0.9 0.9 1.4 1.4 

Size of the solar indirect coil m 2 0.8 0.8 1 1 


Performance factor (upper indirect coil) 2) 

Continuous output (upper indirect coil) at 

80/45/10 °C 3) 

16/2 Specification for the Logalux SL… mono-mode and dual-mode thermosiphon cylinders for DHW heating 


2) In accordance with DIN 4708 when heating to a cylinder temperature of 60 °C and with a heating water flow temperature of 80 °C 


16 

ØD 

ØD Sp 

AW 

EZ 

R6 

EK, EL 

R14 

VS1 

R6 

RS1 

R6 

H 

H AW 

H EZ 

H EK, EL 

H VS1 

H RS1 

8 

Mg 

M1 

M2 

M3 

M4 

Logalux SL300-1 

Mg Magnesium anode 

M1–M4 Temperature measuring points; 

assignment subject to system 

components, hydraulics and control 

units 

EH 

inch 

mm 

R1 

1393 

R1 

1393 


R1 

1392 

R1 

1692 

kWh/24h 2.51 2.51 2.85 3.48 

N L – 2.3 4.1 6.7 

kW (l/h) – (–) 34.3 (843) 34.3 (843) 34.3 (843) 

Number of collectors ➔ 83/2, 86/2 ➔ 83/2, 86/2 ➔ 83/2, 86/2 ➔ 83/2, 86/2 

Weight (net) kg 135 151 197 223 

Max. operating pressure (solar circuit/heating water/DHW) bar 8/–/10 8/25/10 8/25/10 8/25/10 

Max. operating temperature (solar circuit/heating 

water/DHW) 

°C 135/–/95 135/160/95 135/160/95 135/160/95 

ØD 

ØD Sp 

Logalux SL…-2 

Aw 

VS 

R1 

M 

EZ 

R6 

RS 

R1 

EK, EL 

R14 

VS1 

R6 

RS1 

R6 

H 

H AW 

H VS 

H EZ 

H RS 

H EK, EL 

H VS1 

H RS1 

8 

Mg 

Fixing clips M1 to M4 for temperature sensors 

are shown offset in the side view. 

EH 

Plan view 

A1 

Bottom view 

M 1–M4 

RS1 

VS1 

A2


2.2.3 Combi cylinder Logalux P750 S and thermosiphon Combi cylinder 

Logalux PL750/2S and PL1000/2S for DHW and central heating backup 

Combi cylinders are designed for solar DHW heating in 

combination with solar central heating backup. Their 

compact design provides a favourable ratio between 

external surface area and volume, meaning that 

cylinder losses are minimised. All Logalux combi 

cylinders are fitted with a 100 mm thick, CFC-free 

insulation jacket made from flexible polyurethane 

foam. They also have the advantage of simple 

hydraulics with few mechanical components. 

Selected features and characteristics of the Logalux 

P750 S combi cylinder 

● Internal DHW cylinder with Buderus thermoglazing 

and magnesium anode for corrosion protection 

● Large smooth tube indirect coils for optimum 

utilisation of solar energy 

● All connections on the DHW side are at the top, all 

connections on the heating water and solar side are 

on the cylinder side. 

● Solar indirect coil in the heating water resulting in 

no risk of scaling. 

Design and operation of the Logalux P750 S combi 

cylinder 

There is a DHW cylinder in the top part of the thermal 

store that is designed in accordance with the double 

jacket principle. Cold water enters this section from 

above. A solar indirect coil (item 7 ➔ 17/1) is 

connected to the side of the lower section. This first 

heats the heating buffer water (item 6 ➔ 17/1). After a 

short time the DHW in the standby part at the top 

(item 4 ➔ 17/1) reaches the set temperature, meaning 

that DHW can be drawn from the top. The return 

connection at the bottom of the standby section must 

be used to reheat the DHW by a conventional boiler 

(➔ 55/2). A return temperature limiter (➔ page 55) or 

an HZG kit (➔ page 31) in combination with an SC40 

solar control unit or solar function module FM443 is 

recommended for connecting to the heating system. 

17/1 Design of the Logalux P750 S combi cylinder 

Caption 



3 Sensor well 

4 DHW standby part 


6 Thermal store section 




1 

2 

3 

4 

5 

6 

7 

17

2 


Selected features and characteristics of the 

Logalux PL…/2S thermosiphon combi cylinder 

● Internal DHW cylinder, conical straight-through 

design, with Buderus thermoglazing and 

magnesium anode for corrosion protection 


heating, surrounded by DHW and running along 

the entire height of the cylinder. 

● Solar indirect coil integrated in the heating lance 

and therefore also surrounded by DHW 

● Significantly improved solar efficiency because the 

solar heating system always heats the coldest 

medium first 

● All connections on the heating side are at the 

cylinder side 

● Solar connection and cold water inlet from below 

Design and operation of the Logalux PL…/2S 

thermosiphon combi cylinder 

The Logalux PL750/2S and PL1000/2S thermosiphon 

combi cylinders have a conical internal body (item 5 

➔ 18/1) for DHW heating. There is a heating lance 

suspended in the DHW that runs along the entire 

height of the cylinder integrating the solar indirect coil 

(item 6 and item 8 ➔ 18/1). The DHW cylinder can 

therefore be heated in accordance with the 

thermosiphon principle using this patented 

stratification system. Subject to the availability of 

adequate insolation, a sensible temperature level is 

reached in the DHW cylinder after only a short time. 

The DHW cylinder is surrounded by a thermal store 

(item 4 ➔ 18/1) that is heated subject to the 

stratification status in the internal body. 

18 

18/1 Design of the Logalux PL750/2S and PL1000/2S thermosiphon 

combi cylinders 

Caption 



3 DHW outlet 

4 Thermal store 

5 Conical internal body 


7 Gravity flaps 





1 

2 

3 

4 

5 

6 

7 

8 

9

Cold water enters the lower section of the conical 

internal body, so that the solar indirect coil and the 

heating lance are in the coldest medium. The heating 

lance has an opening at the bottom that enables the 

cold drinking water to reach the solar indirect coil. 

Here the water is heated by the solar heating system 

and rises upwards in the lance without mixing with the 

colder water that surrounds it. 

There are various outlets with buoyancy-controlled 

gravity flaps at different levels (Pos. 7 ➔ 18/1), through 

which the heated medium reaches the layers with the 

same temperature level in the cylinder (phase 1 

➔ 19/1). After a delay, the heat is then transferred to 

the buffer water in the outer body, enabling the 

thermal store to be heated from top to bottom 

(phase 2 ➔ 19/1). The solar system shuts down 

(phase 3 ➔ 19/2) when the DHW cylinder and the 

thermal store are both fully heated. Drawing hot water 

gradually discharges the DHW cylinder from bottom to 

top. Cold drinking water replaces the DHW drawn 

inside the inner body. Because of the heat-up delay 

between the inner and outer bodies, the internal 

body can be supplied with solar heat again although 

the outer thermal store is still fully heated (phase 4 

➔ 19/2). This makes the system considerably more 

efficient. 

When the DHW cylinder has been almost completely 

drawn off, both the solar indirect coil and the thermal 

store reheat the DHW cylinder (phase 5 ➔ 19/3). If no 

solar yield is available (e.g. during bad weather), the 

thermal store can be reheated using a conventional 

boiler (phase 6 ➔ 19/3) or may be combined with a 

solid fuel boiler (engineering notes ➔ page 58). A 

return temperature controller (➔ page 55) or an HZG 

kit (➔ page 31) in combination with a SC40 solar 

control unit or solar function module FM443 is 

required for connecting to the heating system. 

Caption (➔ 19/1 to 19/3) 

AW DHW outlet 


RS1 Solar return 

VS1 Solar flow 

RS2 Boiler return 

VS3 Boiler flow 

Other connections for alternative heating ➔ 20/1 to 21/2 


EK 

VS1 

RS1 

AW AW 

EK 

VS1 

RS1 

19/1 Heating the thermosiphon combi cylinder via the solar indirect 

coil (1) and delayed thermal store heating (2) 

EK 

VS1 

RS1 

19/2 Drawing DHW from the fully heated cylinder (3) and reheating 

the DHW cylinder (which is cold at the bottom) via the solar 

indirect coil in spite of having a full thermal store (4) 

EK 

VS1 

RS1 

19/3 Reheating the DHW cylinder via the solar indirect coil and the 

thermal store (5) and reheating via a conventional boiler in the 

event of insufficient solar yield (6) 


VS3 

RS2 

Phase 1 Phase 2 

AW AW 

VS3 

RS2 

EK 

VS1 

RS1 


AW AW 

VS3 

RS2 

EK 

VS1 

RS1 


VS3 

RS2 

VS3 

RS2 

VS3 

RS2 

19

2 


Dimensions and specification for the Logalux P750 S combi cylinder 

20/1 Dimensions and connections of the Logalux P750 S combi cylinder for DHW heating and as central heating backup 

Logalux combi cylinder P750 S 

Cylinder diameter with/without insulation ØD/ØD Sp mm 1000/800 

Cold water inlet ØEK inch R6" 

Draining the heating system ØEL inch R14 

Cylinder return on the solar side ØRS1 inch R1 

Cylinder flow on the solar side ØVS1 inch R1 

Return, oil/gas fired/condensing boilers for DHW heating ØRS2 inch R14 

Flow, oil/gas fired/condensing boiler for DHW heating ØVS3 inch R14 

Return, oil/gas fired boiler ØRS3 inch R14 

Return, heating circuits ØRS4 inch R14 

Flow, heating circuits ØVS4 inch R14 

Flow, solid fuel boiler ØVS2 inch R14 

DHW circulation inlet ØEZ inch R 6" 

DHW outlet ØAW inch R 6" 

Capacity l 750 

Capacity, thermal store only l ≈400 

Capacity, DHW l ≈160 

Content, solar indirect coil l 16.4 

Size, solar indirect coil m 2 2.15 


Performance factor 2) 

Continuous output at 80/45/10 °C 3) 

20/2 Specification for the Logalux PL750 S combi cylinder for DHW and central heating backup 




20 

M1 

M2 

M3 

M4 

M5 

M6 

M7 

M8 

ØD 

ØD sp 

M 

VS2 

VS3 

RS2 

VS 4 

VS1 

RS3 

RS1 

RS4/EL 

1920 

1668 

1513 

1033 

911 

788 

500 

370 

215 

8 

kWh/24h 3.7 


N L 

M 1–M 8 

EK 

EZ/AW 

kW (l/h) 28 (688) 

Number of collectors ➔ 86/1 

Weight (net) kg 262 

Max. operating pressure (solar indirect coil/heating water/DHW) bar 8/3/10 

Max. operating temperature (heating water/DHW) °C 95/95 

AW/EZ 

M 

MB1 

550 

Plan view Bottom view 

MB1 DHW measuring point 

M1–M8 Temperature measuring 

points; assignment depending 

on components, hydraulics 

and control units in the system 

3 

640 

Fixing clips M1 to M8 for temperature 

sensors are shown offset in the side view.


Dimensions and specification of the Logalux PL…/2S thermosiphon combi cylinder 

M1 

M2 

M3 

M4 

M5 

M6 

M7 

M8 

EL2 

21/1 Dimensions and connections of the Logalux PL…/2S thermosiphon combi cylinder 

Logalux thermosiphon combi cylinder PL750/2S PL1000/2S 

Cylinder diameter with/without insulation ØD/ØD Sp mm 1000/800 1100/900 

Cold water inlet ØEK inch R1 R1 

Draining the heating system ØEL inch R14 R14 

Solar/DHW draining ØEL1/ØEL2 inch R 6" R 6" 

Cylinder return on the solar side ØRS1 inch R 6" R 6" 

Cylinder flow on the solar side ØVS1 inch R 6" R 6" 

Return, oil/gas fired/condensing boiler for DHW heating ØRS2 inch R14 R14 

Flow, oil/gas fired/condensing boiler for DHW heating ØVS3 inch R14 R14 

Return, oil/gas fired boiler ØRS3 inch R14 R14 

Flow, oil/gas fired boiler ØVS5 inch R14 R14 

Return, heating circuits ØRS4 inch R14 R14 

Flow, heating circuits ØVS4 inch R14 R14 

Return, solid fuel boiler ØRS5 inch R14 R14 

Flow, solid fuel boiler ØVS2 inch R14 R14 

DHW circulation inlet ØEZ inch R 6" R 6" 

DHW outlet ØAW inch R 6" R 6" 

Immersion heater ØEH inch R15 R15 

Capacity l 750 940 

Capacity, thermal store only l ≈275 ≈380 

Capacity, DHW total/standby part l ≈300/≈150 ≈300/≈150 

Content, solar indirect coil l 1.4 1.4 

Size of the solar indirect coil m 2 1.0 1.2 


Performance factor 2) 

ØD 

ØD sp 

Continuous output at 80/45/10 °C 3) 

M 

VS2 

VS3 

RS2 

VS4 

EH/VS5 

RS3 

RS4 

RS5/EL 

VS1 

RS1/EL1 

EK 

1920 

550 

1668 

AW/EZ 

1513 

EH 

M 

MB1 

MB2 

RS1 

EK 

1033 

911 

788 

500 

370 

M 1–M8 

EZ/AW 

Mg 

640 

VS1 

EL2 

215 


170 

100 MB1 DHW measuring point 


8 

MB2 Solar measuring point 


points; subject to system 

configuration 

sensors are shown offset in the side view. 

kWh/24h 3.7 4.57 

N L 3.8 3.8 

kW (l/h) 28 (688) 28 (688) 

Number of collectors ➔ 86/1 ➔ 86/1 

Weight (net) kg 252 266 

Max. operating pressure (solar indirect coil/heating water/DHW) bar 8/3/10 8/3/10 

Max. operating temperature (heating water/DHW) °C 95/95 95/95 

21/2 Specification for the Logalux PL…/2S combi cylinder for DHW and central heating backup 





21

2 


2.2.4 Duo FWS combi cylinder 


● Internal corrugated stainless steel pipe (material 

W1.4404) for hygienic DHW heating 

● High degree of DHW convenience through a 

corrugated pipe with a large transfer area 

● Large smooth-tube indirect coil for optimum solar 

utilisation 

● Solar indirect coil in the heating water preventing a 

risk of scaling 

● Slimline version for easy handling 

● All DHW and heating water connections are on the 

cylinder side 

● Sensor terminal strip for variable sensor positioning 


An internal corrugated stainless steel pipe (item 2 ➔ 22/1) 

is wound onto a supporting structure. The corrugated 

pipe has an extremely large surface in its upper area to 

achieve a high degree of DHW convenience. The lower 

section is sized so that the thermal store is efficiently 

cooled by the cold water. This optimises the solar yield. 

If no solar yield is available, the thermal store can be 

reheated using a conventional boiler or can be 

combined with a solid fuel boiler. The thermal store 

temperature (top) indirectly specifies the DHW 

temperature and has a major influence on the drawing 

capacity (DHW convenience). A return temperature 

controller (➔ page 55) or an HZG kit (➔ page 41) in 

combination with the FM443 solar function module 

FM443 or the SC40 solar control unit is required for 

connecting to the heating system. 

22 

22/1 Design of the Duo FWS combi cylinder 

Caption 

1 DHW outlet 

2 corrugated stainless steel pipe 

3 Thermal store section 



Dimensions, connections and specification ➔ 23/1 and 23/2 


1 

2 

3 

4 

5

Dimensions and specification of the Duo FS combi cylinder 

AB 

EK 

ØD 

Side view with indirect coil and 

corrugated pipe heat exchanger 

VS2 

VS3 

23/1 Dimensions and specification of the Duo FWS combi cylinder 


Combi cylinder Duo FWS750 Duo FWS1000 

Cylinder diameter with thermal insulation 80 mm 

120 mm 

VS4 

RS2 

VS1 

RS5 

RS3 

RS1 

RS4 

H 

120 

ØD W 

ØD W 

Cylinder diameter without thermal insulation Dia. D mm 750 800 

Height H mm 1948 2208 

Height with thermal insulation 80 mm HW mm 1985 

2260 

120 mm HW mm 2025 

2300 

Cold water inlet ØEK 

inch R14 

R14 

HEK mm 

270 

280 

Cylinder return on the solar side ØRS1 

inch 

G1 

G1 

HRS1 mm 

370 

380 

Cylinder flow on the solar side ØVS1 

inch 

G1 

G1 

HVS1 mm 

930 

980 

Return, oil/gas fired/condensing boiler for DHW heating/heating ØRS2 

inch G15 

G15 

circuit flow/pellet boiler return 

HRS2 mm 1030 

1080 

Return, oil/gas fired/condensing boiler for DHW heating ØRS5 

inch G15 

G15 

(alternative) 

HRS5 mm 

830 

880 

Flow, oil/gas fired/condensing boiler for DHW heating ØVS3 

inch G15 

G15 

HVS3 mm 1570 

1830 

Return, heating circuits ØRS3 

inch G15 

G15 

HRS3 mm 

470 

480 

Flow, pellet system heating circuits ØVS4 

inch G15 

G15 

HVS4 mm 1230 

1280 

23/2 Specification of Duo FWS combi cylinder 

Continued on the next page 

48 

A A 

H AB 

H EK 

Ø600 

A – A 

mm 

mm 

910 

990 


H VS2 

H VS3 

H VS4 

HRS2 HVS1 HRS5 HRS3 HRS1 HRS4 Side view without indirect coil or 

corrugated pipe heat exchanger 

Plan view without indirect coil 

1450 

G1½ 

960 

1040 

120 

Side view without corrugated 

pipe heat exchanger 

23

2 


Combi cylinder Duo FWS750 Duo FWS1000 

Return, solid fuel boiler ØRS4 

HRS4 Flow, pellet boiler/solid fuel boiler ØVS2 

HVS2 DHW outlet ØAB 

HAB 24 

inch 

mm 

inch 

mm 

inch 

mm 

G15 

280 

G15 

1660 

R14 

1670 


G15 

290 

G15 

1920 

R14 

1930 

Cylinder capacity l 750 1000 

Capacity, corrugated stainless steel pipe (DHW) l 38 38 

Size of the corrugated stainless steel pipe m 2 7 7 

Content, solar indirect coil l 11 13 

Size of the solar indirect coil m 2 2.2 2.7 

Performance factor1) at a boiler output of 30 kW 

at a boiler output of 45 kW 

Drawing capacity2) Draw-off rate 10 l/min 

Draw-off rate 20 l/min 

N L 

N L 

Number of collectors ➔ 86/1 ➔ 86/1 

Weight (net) kg 240 270 

Max. operating pressure (heating water/DHW/solar circuit) bar 3/10/10 3/10/10 

Max. operating temperature (heating water/DHW/solar circuit) °C 95/95/110 95/95/110 

23/2 Specification of Duo FWS combi cylinder 

1) With reference to DIN 4708 T3 

2) Without reheating, cylinder partially heated at 70 °C, DHW temperature 45 °C 

l 

l 

3.2 

– 

275 

218 

– 

4.2 

407 

324


2.2.5 Thermosiphonthermal stores Logalux PL750, PL1000 and PL1500 

as heating thermal stores 


● Suitable for solar arrays with up to 8 collectors (with 

Logalux PL750 and PL1000) or up to 16 collectors 

(with Logalux PL1500) and for heat supplied from 

other sustainable energy sources 


heating 

● Buoyancy-controlled plastic gravity flaps 

● Extremely suitable for use as a heating thermal store 

because of its large buffer volume (e.g. in dualcylinder 

systems) 

● Encased in 100 mm thick, CFC-free insulation jacket 

made from flexible polyurethane foam in a blue 

jacket 


This sheet steel thermosiphon thermal store is 

available in three versions: 

● Logalux PL750 with a content of 750 l 



The Logalux PL1500 thermosiphon thermal store has 

two solar indirect coils. 

➔ Detailed description of the thermosiphon 

equipment ➔ page 14 ff. 



2 Cylinder 


4 Gravity flap 


25/1 Logalux PL750 and PL1000 thermosiphon thermal stores 

25/2 Logalux PL1500 thermosiphon thermal store 


1 

2 

3 

4 

5 

V 

R 

25

2 


Dimensions and specification of the Logalux PL750, PL1000 and PL1500 thermosiphon thermal stores 

26/1 Dimensions and connections of the Logalux PL…thermosiphon thermal store 

Logalux thermosiphon thermal store PL750 PL1000 PL1500 

Cylinder diameter with/without insulation ØD/ØD Sp mm 1000/800 1100/900 1400/1200 

Height H mm 1920 1920 1900 

Cylinder return on the solar side H RS1 mm 100 100 100 

Cylinder flow on the solar side H VS1 mm 170 170 170 

Cylinder return ØRS2–RS4 

HRS2 HRS3 HRS4 Cylinder flow ØVS2–VS4 

HVS2 HVS3 HVS4 Feet centres A1 

A2 

26 

M1 

M2 

M3 

M4 

ØD 

ØDSp E 

R 5 

VS2 

VS3 

VS 4 

RS 4 

RS2 

RS3 

VS1 

R6 

RS1 

R6 

Side view 

Logalux PL750, PL1000, PL1500 

M 

H 

H E 

H VS2 

H VS3 

HVS4 HRS4 H RS2 

H RS3 

H VS1 

H RS1 

8 

inch 

mm 

mm 

mm 

inch 

mm 

mm 

mm 

mm 

mm 

R14 

370 

215 

1033 

R14 

1668 

1513 

1033 

555 

641 


R14 

370 

215 

1033 

R14 

1668 

1513 

1033 

555 

641 

Cylinder capacity l 750 1000 1500 

Content, solar indirect coil l 2.4 2.4 5.4 

Size of the solar indirect coil m 2 

3 3 7.2 


kWh/24h 3.7 4.57 5.3 

Number of collectors ➔ 86/3 ➔ 86/3 ➔ 86/3 

Weight (net) kg 212 226 450 

Max. operating pressure (solar indirect coil/heating water) bar 8/3 8/3 8/3 

Max. operating temperature (heating water) °C 110 110 110 

M 1–M 4 

26/2 Specification of Logalux PL... thermosiphon thermal store for solar central heating backup 


M 

E 


Logalux PL750, PL1000 

A1 


points; assignment subject to 

system components, 

hydraulics and control units 


sensors are shown offset in the side view. 

RS1 

VS1 

A2 

Bottom view 

Logalux PL1500 

VS2–VS4 Use subject to system 

components and hydraulics 

RS2–RS4 Use subject to system 

components and hydraulics 

R15 

522 

284 

943 

R15 

1601 

1363 

943 

850 

980 

RS1 

VS1

2.3 Solar control unit 

2.3.1 Selection aids 

Selection and standard delivery of control unit 

Various control units and function modules are 

available depending on the application area and the 

boiler control unit: 

● Heat source with Logamatic EMS control system: 

– Solar heating systems for DHW heating: 

Programming unit RC35 with 

Solar function module SM10 (➔ page 29) 

– Solar heating systems for DHW and central 

heating backup: 

Logamatic 4121 control unit with 

Solar function module FM443 (➔ page 31) 

2.3.2 Control strategies 

Temperature differential control 

In "Automatic" mode the solar control unit monitors 

whether the solar cylinder can be heated with solar 

energy. To do this, the control unit compares the 

collector temperature using the FSK sensor and the 

temperature in the lower area of the cylinder (FSS 

sensor). If there is adequate insolation, i.e. the set 

temperature differential between the collector and the 

cylinder is exceeded, the solar circuit pump starts and 

the cylinder is heated. 

After a long period of insolation and low DHW 

consumption, high temperatures occur in the cylinder. 

The solar circuit control unit switches the solar circuit 

pump off when the maximum cylinder temperature is 

been reached during heating. 

Temperature differential control unit SC20 for one consumer 

V 

FSK 

SP1 

Logasol 

SKN3.0 

SKS4.0 

AW 

SP1 Logasol 

SKN3.0 

SKS4.0 

AW 

Twin-Tube 

Twin-Tube 

Logasol 

KS0105SC20 

R 

MAG 

230 V 

50 Hz 

FE 

AW 

FSX 

FSS 

WWM 


SL400-2, SL500-2 

VS 

RS 

EK 

V 

FSK 


Logasol 

KS0105SC20 

R 

MAG 

230 V 

50 Hz 

FE 

AW 

FSX 

FSS 

WWM 


SL400-2, SL500-2 

● Heat source with Logamatic 2107 control unit: 


● Heat source with Logamatic 4000 control unit: 


● Heat source with third party control unit: 

Control unit SC20 or SC40 (➔ page 34 f.) 

The standard delivery of the solar function modules or 

the SC20 and SC40 control units includes: 

● One collector temperature sensor FSK 

(NTC 20 K, Ø6 mm, 2.5m lead) and 

● One collector temperature sensor FSS 

(NTC 10 K, Ø9.7 mm, 3.1m lead) 

The maximum cylinder temperature can be adjusted 

at the control unit. 

If there is little insolation the pump speed is reduced to 

maintain a constant temperature differential. This 

allows the cylinder to be heated with low power 

consumption. The solar control unit does not switch 

the pump off until the temperature differential has 

dropped below the minimum temperature differential, 

and the speed of the circulation pump has already 

been reduced to its minimum value by the solar control 

unit. 

If the cylinder temperature is inadequate to provide 

DHW convenience a heating circuit control unit 

ensures the reheating of the cylinder by a conventional 

heat source. 

27/1 Function diagram of solar DHW heating with temperature differential control unit SC20 and flat-plate collectors with the system enabled 

(left) and conventional reheating if there is insufficient insolation (right) 


VS 

RS 

EK 

KS0105SC20 Logasol complete station 

KS0105 with integral solar 

control unit SC20 

FSK Collector temperature sensor 

FSS Cylinder temperature sensor 

(bottom) 

FSX Cylinder temperature sensor 

(top; optional) 

Other abbreviations ➔ page 148 

27

2 


Double-Match-Flow 

Solar function modules SM10, FM443 and control units 

SC20 and SC40 provide optimised heating of the 

thermosiphon cylinder using a special high-flow/lowflow 

strategy. The solar control unit monitors the 

cylinder heating status using a threshold sensor 

located in the centre of the cylinder. Depending on the 

heating status the control unit switches to high-flow or 

low-flow operation, whichever is currently the best. 

This changeover facility is known as Double-Match- 

Flow. 

Prioritised heating of the standby part 

with low-flow operation 

In low-flow operation the control unit attempts to 

achieve a temperature differential between the 

collector (FLK sensor) and the cylinder (FSS sensor). 

This is done by varying the flow rate via the solar 

circuit pump speed. 

The standby part of the thermosiphon cylinder is 

heated with priority using the resulting high flow 

temperature. Conventional cylinder reheating is 

therefore suppressed as much as possible conserving 

primary energy. 

Standard thermosiphon cylinder heating 

in high-flow operation 

The solar control unit increases the speed of the solar 

circuit pump if the standby part of the cylinder has 

been heated up to 45 °C (FSX threshold sensor). The set 

temperature differential between the collector (FSK 

sensor) and the lower cylinder area (FSS sensor) is 15 K. 

The system is then operating with a lower flow 

temperature. With this operating mode, less heat is lost 

in the collector circuit, and system efficiency is 

optimised during cylinder heating. 

Subject to sufficient collector output being available, 

the control system reaches the set temperature 

differential and continues to heat the cylinder with 

optimum collector efficiency. If the set temperature 

differential can no longer be achieved, the control 

system uses the available solar heat at the slowest 

pump speed until the shut-off criterion is reached. The 

thermosiphon cylinder stores the heated water in the 

correct temperature layer (➔ 28/3). If the temperature 

differential drops below 5 K, the control unit switches 

the solar circuit pump off. 

Caption (➔ 28/1 to 28/3) 

ΔJ Temperature differential between collector (FSK sensor) 

and lower cylinder area (FSS1 sensor) 


V Solar flow 


28 

Δϑ = 30 K 

28/1 Prioritised heating of the standby section of a thermosiphon 

cylinder with Δϑ = 30 K using a variable, slow pump speed in 

low-flow operation, until 45 °C is reached at the FSX threshold 

sensor 

Δϑ = 15 K 

FSS1 

V 

28/2 Heating of a thermosiphon cylinder with Δϑ = 15K with strong 

insolation using a fast pump speed in high-flow operation 

Δϑ < 15 K 

28/3 Heating of a thermosiphon cylinder with the maximum 

possible flow temperature (Δϑ < 15 K) using the slowest pump 

speed with low insolation 


AW 

R 

AW 

FSS1 

V 

R 

AW 

FSS1 

V 

R 

FSX 

EK 

FSX 

FSX 

EK 

VS 

RS 

VS 

RS 

VS 

RS

Solar optimisation function of function modules SM10, FM244 and FM443 

With the solar optimisation function, conventional 

energy is conserved and solar yield is increased by 

integrating the solar control in the boiler control unit. 

The consumption of reheating (primary) energy for 

heating DHW is reduced by up to 10% compared to 

conventional solar control units. The number of burner 

starts is reduced by up to 24%. 

60 

With the solar optimisation function the control unit 

captures whether 

ϑSp ● solar yield is available, and whether 

˚C 

● the stored amount of heat is sufficient to provide 

45 

DHW. 

The general objective of the control unit is to reduce the 

temporary set DHW temperature as much as possible 

whilst at the same time ensuring user convenience, to 

prevent reheating by the boiler. 

The standby volume of the cylinder is designed to cover 

the DHW demand at a storage temperature of 60 °C. If 

the lower region of the cylinder is heated by solar 

energy, then the boiler can heat the water to useful 

temperatures that much more rapidly. Higher 

temperatures in the lower cylinder region therefore 

enable a reduction of the set reheating temperature, 

saving primary energy. The lowest acceptable DHW 

temperature can be set by the user using the 

"MINSOLAR" parameter within a range of 30 °C to 

54 °C. With DHW heating using the flow-through 

principle, this temperature relates to the water in the 

upper section of the thermal store. 

2.3.3 Solar control units and function modules 


Logamatic EMS control system with solar function module SM10 

Features and characteristics 

● Control of solar DHW heating for heat sources with 

EMS and control unit RC35 

● Up to 10% primary energy saving and up to 24% 

fewer burner starts compared to conventional solar 

control units by means of system integration in the 

heating control unit (solar optimisation function) 

5:30 8:00 10:10 17:00 22:00 

29/1 "Solar yield optimisation" control function 

Caption 

ϑ Sp DHW temperature in the cylinder 

t Time 

a Insolation 

b DHW temperature at the top of the cylinder 

c DHW temperature at the bottom of the cylinder 

d Set DHW temperature 

➊ First draw-off (reheating) 

➋ Second draw-off (adequate solar yield) 

➋ Third draw-off (adequate cylinder temperature) 

● Prioritised heating of the standby section of 

thermosiphon cylinders and energy-optimised 

operation control using Double-Match-Flow 

(FSX sensor also used as threshold sensor) 

● Optional dual-cylinder systems (cylinders connected 

in series) for DHW heating in combination with 

KR-VWS (daily heating of pre-heating stage and 

stratification) or SC10 (water transfer only) 


a 

b 

c 

t 

d 

29

2 


● Different versions: 

– SM10 inside: SM10 integrated in 

Logasol KS0105SM1 complete station 

– SM10: Module for wall mounting or integration in 

a slot in the heat source (please observe heat 

source details), only suitable for combining with 

Logasol KS01 complete stations without control 

system 


1 Access to equipment fuse 

2 Solar function module SM10 

3 Access to replacement fuse 

4 Indicator (LED) for operation and alarm indication 

5 Wall retainer 

6 Terminal cover 

Logamatic 2107 control unit with solar function module FM244 


● Combined boiler/solar control unit for low 

temperature boilers with low and moderate heating 

demand and solar DHW heating 

● Up to 10 % primary energy saving and up to 24% 



Logamatic 2107 control unit (solar optimisation 

function) 

● Optional solar heating systems for central heating 

backup in combination with the RW return 

temperature limiter 

● Optional dual-cylinder systems (cylinders connected 

in series) for DHW heating in combination with 

SC10 (water transfer only) 

● Only for combining with Logasol KS01... complete 

stations without control unit 

● Solar function module FM244 is integrated in 

control unit 2107 

30 

1 2 3 4 

30/1 Solar-function module SM10 for wall mounting 


Components that can be used for solar operation 

(with solar function module FM244): 

1 Digital display 

2 User interface with cover 

3 Rotary selector 

4 Operating mode buttons 

Additional boiler control components: 

5 Control unit ON/OFF switch 

6 Burner control selector switch 

7 Control unit power fuse 

8 Flue gas test button (chimney sweep) 

9 Boiler control thermostat 

10 Boiler high limit safety cut-out 


1 

2 3 4 

6 5 

10 9 8 7 6 5 

30/2 Boiler control unit Logamatic 2107 with fitted solar-function 

module FM244


Logamatic 4000 control system with solar function module FM443 


● Solar function module FM433 makes enables the 

control of DHW heating or DHW and central 

heating backup in systems with a maximum of two 

solar consumers (cylinders) 

● Up to 10% primary energy saving and up to 24% 



heating control unit (solar optimisation function) 

● Prioritised heating of the standby part of 


operation control using Double-Match-Flow (FSX 

sensor also used as threshold sensor) 

● Can be used for EMS heat sources with the 

Logamatic 4121 control unit; required for solar 

heating systems for DHW heating with central 

heating backup because of the external heat 

detection function 

● Optional integrated heat meter function in 

combination with WMZ1.2 accessory kit 

● Entire system, including the solar control unit, can 

be operated from the living room using the MEC2 

programming unit 

● Only for combining with Logasol KS01... complete 

stations without control unit 

● Stratification of dual-mode cylinders 

● Transfer of hot water in dual-cylinder systems for 

DHW heating 

● Intelligent buffer management 

● Statistics function 

● Solar function module FM443 can be integrated in a 

digital control unit of the Logamatic 4000 modular 

control system 

31/1 Solar function module FM443 

Caption 

1 Connection plug 

2 LED indicator, module fault 

3 LED maximum collector temperature 

4 LED solar circuit pump 2 (secondary pump) running 

5 LED solar circuit pump 2 running or three-way diverter valve in 

solar circuit 2 position 

6 LED three-way diverter valve in solar circuit 1 position 

7 Manual switch solar circuit selection 

8 PCB 

9 Manual switch, solar circuit function 1 

10 LED three-way diverter valve in direction "Central heating 

backup via thermal store off" or "Pump off" (bypass operation) 

11 LED three-way diverter valve in direction "Central heating 

backup via thermal store on" or "Pump running" (thermal store 

operation) 

12 LED solar circuit pump 1 running 

13 LED maximum temperature in cylinder 1 


13 

12 

11 

10 

9 

1 

2 

3 

4 

5 

6 

7 

8 

31

2 


Stratification 

If the pump function is set to "Stratification" with dualmode 

solar cylinders, the pump that is connected is 

used to heat up the solar pre-heating stage to 60 °C 

once every day, if required, to provide pasteurisation in 

accordance with DVGW Code of Practice W 551 or for 

the pasteurisation of the solar pre-heating stage. 

Transfer of hot water 

If the pump function is set to "transfer", with cylinders 

connected in series the connected pump is used to 

transfer the water from the solar cylinder and the 

cylinder that is heated via the boiler. As soon as the 

solar cylinder is hotter than the cylinder that is heated 

by the boiler, pump PUM is switched on and the water 

in the cylinders is transferred. 

This pump is also used to heat the solar cylinder, i. e. 

the solar pre-heating stage, to 60 °C once every day if 

required to pasteurise in accordance with the DVGW 

Code of Practice W 551 or for the pasteurisation of the 

solar pre-heating stage. 

32 

32/1 Water transfer in a circuit with one solar cylinder 

32/2 Transfer of hot water between cylinders connected in series 


FSS 

FSX 

FSS 

PUM 

M 

PUM 

FSX

Logamatic SC10 solar control unit 


● Autonomous solar control unit with temperature 

differential control for simple solar heating systems 

● Easy operation and function control of the 

temperature differential control unit with two sensor 

inputs and one switching output 

● Controller for wall mounting, function and 

temperature displayed via segment LCD 

● Can be used to transfer hot water between two 

cylinders, e.g. the heat stored in the pre-heating 

cylinder can be transferred to the standby cylinder 

● Used for buffer bypass circuits in solar heating 

systems for central heating backup. The 

temperature comparison results in the volume flow 

being routed either to the thermal store or to the 

heating return. This function can also be used in 

combination with wood burning boilers. 

Temperature differential control 

The required temperature differential can be set to 

between 4 K and 20 K (factory setting 10 K). The pump 

starts if the set temperature differential between the 

collector (FSK sensor) and the bottom of the cylinder 

(FSS sensor) is exceeded. The control unit switches the 

pump off when the temperature differential drops 

below this value again. 

A maximum cylinder temperature of between 20 °C 

and 90 °C can also be set (factory setting 60 °C). When 

the cylinder reaches the maximum temperature (FSS 

sensor), the control unit switches the pump off. 

Special displays and controls of the SC10 solar 

control unit 

The temperature settings can be viewed on the control 

unit display. The current values of connected 

temperature sensors 1 and 2 are displayed together 

with the respective sensor number. 

Standard delivery 

The standard delivery includes: 


(NTC 20K, Ø6 mm, 2.5m lead) 


(NTC 10K, Ø9.7 mm, 3.1m lead) 


5 

33/1 Logamatic SC10 solar control unit 

Caption 

1 Segment LCD 

2 Direction key "Up" 

3 Function key "SET" 

4 Direction key "Down" 

5 Operating mode keys (concealed) 

Application Recommended switch-on 

temperature differential 

K 

Operating a solar 

10 

heating system 

Buffer bypass circuit 

(three-way valve) 

6 

Transfer between 

two cylinders 

10 

33/2 Recommended switch-on temperature differential 


1 

2 

3 

4 

33

2 




● Autonomous solar heating system control unit for 

DHW heating, independently of the heat generator 

control unit 

● Prioritised heating of the standby part of 


operation control using Double-Match-Flow (FSX 

threshold sensor available as accessory, AS1 or 

AS1.6 cylinder connection kit) 


– SC20 integrated in the Logasol KS0105 complete 

station 

– SC20 for wall mounting in combination with 

Logasol KS01 

● Easy operation and monitoring of single consumer 

systems with three sensor inputs and one switching 

output for one variable speed solar circuit pump 

with variable lower modulation limit 

● Backlit segment LCD with animated system 

pictograph. Different system values (temperature 

values, hours run, pump speed) can be called up in 

automatic mode 

● The pump is switched off when the maximum 

collector temperature is exceeded. The pump will 

not start if the temperature drops below the 

minimum collector temperature (20 °C), even if the 

other switch-on conditions are met 

● With the tube collector function the solar circuit 

pump is activated briefly every 15 minutes from a 

collector temperature of 20 °C to pump warm solar 

fluid to the sensor 


control unit 

As well the above parameters, the digital display also 

allows the speed of the solar circuit pump to be 

displayed in percent. 

The following values can be optionally recorded with 

the FSX sensor accessory (cylinder connection kit AS1): 

● The top cylinder temperature in the standby part of 

the DHW cylinder or 

● The mid-cylinder temperature for Double-Match- 

Flow (here the FSX threshold sensor) 




(NTC 20K, Ø6 mm, 2.5m lead) 



34 



1 System pictograph 

2 Segment LCD 


4 Function key "OK" 

5 Direction key "Back" 

34/2 Segment LCD of the Logamatic SC20 solar control unit 


1 Display "Maximum collector temperature or minimum collector 

temperature" 

2 "Temperature sensor" symbol 

3 Segment LCD 

4 Multifunction display (temperature, hours run, etc.) 

5 "Maximum cylinder temperature" display 

6 Animated solar circuit 


6 

1 

min/max 

5 

1 

2 

T1 T1 

T3 T3 

max max 

T2 T2 

2 

ΔT T on on 

- 

+ 

4 

3 

3 

max max 

DMF DMF 

reset reset 

�i 

❄ 

˚C 

% 

h 

4 

5

Control unit function 

The required temperature differential between the two 

connected temperature sensors can be set to between 

7 K and 20 K in automatic mode (factory setting 10 K). 

The pump starts if this temperature differential is 

exceeded between the collector temperature sensor 

(FSK sensor) and the bottom of the cylinder (FSS 

sensor). An animated display of the movement of the 

solar fluid appears on the display (➔ 34/2, item 6). The 

efficiency of the solar system is increased by the 

variable speed control provided by the SC20. A 

minimum speed can also be stored. When the 

temperature differential drops below this value again 

the control unit switches the pump off. To protect the 

pump, it is automatically activated for about 3 seconds 

approximately 24 hours after it was last operated 

(pump kick). 

The different system values (temperature values, hours 

run, pump speed) can be called up using the rotary 



● Autonomous solar heating system control unit for 

different applications, independent of the heat 

source, with 27 selectable solar heating systems, 

from DHW heating and central heating backup to 

swimming pool water heating 


– SC40 integrated in the Logasol KS 0105 complete 

station 

– SC40 for wall mounting in combination with 

Logasol KS01 

● Easy operation and monitoring of systems with up 

to four consumers, eight sensor inputs and five 

switching outputs, two of which are for variable 

speed solar circuit pumps with adjustable lower 

modulation limit 

● Backlit LCD graphic with depiction of the selected 

solar system. Different system values (pump status, 

temperature values, selected function, fault 

messages) can be called up in automatic mode 

● RS232 interface for transferring data and integral 

heat meter (accessory WMZ 1.2 required) 

● Integrated circuit for buffer bypass circuit in solar 

heating systems for central heating backup 

● Daily heating of the pre-heating cylinder to provide 

pasteurisation 

● In solar heating systems with a pre-heating cylinder 

and standby cylinder, the cylinder contents are 

transferred by actuating a pump as soon as the 

temperature of the standby cylinder drops below the 

temperature of the pre-heating cylinder 

● Priority definition with two consumers in the solar 

heating system and actuation of the 2nd consumer 

via a pump or a three-way diverter valve 


selector (➔ 34/1, item 3). The temperature values are 

assigned in the pictograph using item numbers. 

The SC20 solar control unit also enables the setting of 

a maximum cylinder temperature between 20 °C and 

90 °C, which is displayed in the system pictograph, if 

required. Reaching of the maximum or minimum 

collector temperature is also visually indicated on the 

segment LCD, and the pump switched off if they are 

exceeded. If the temperature drops below the 

minimum collector temperature the pump will not 

start, even if the other switch-on conditions are met. 

The tube collector function that is integrated in the 

SC20 provides a pump kick to optimise the operation 

of vacuum tube collectors. 

The combination of the Double-Match-Flow function 

(only possible with additional FSX sensor as accessory 

to the AS1 cylinder connection kit) and the speed 

● Optional actuation for two solar heating circuit 

pumps for a separate operation of two collector 

arrays, e.g. with east/west orientation 

● Actuation of an external plate-type heat exchanger 

for heating the solar cylinder 

● Collector array cooling for reducing the stagnation 

times by means of adapted solar circuit pump 

operation 

● With the tube collector function, the solar circuit 

pump is activated briefly every 15 minutes at a 

collector temperature from 20 °C to pump warm 

solar fluid to the sensor 


control unit 

The relevant system pictograph is selected from the 27 

pre-programmed hydraulic schemes, and subsequently 

saved to the control unit. 




(NTC 20 K, Ø6 mm, 2.5m lead) 


(NTC 10 K, Ø9.7 mm, 3.1m lead) 


35

2 


Control unit function 

The control unit is divided into two operating levels. 

Various system values (temperatures, hours run, pump 

speed, amount of heat and bypass valve setting) can be 

displayed at the display level. Functions can be selected 

and settings made and modified at the service level 

The system selection function is used to select the 

standard system at the SC40 solar control unit and the 

hydraulic scheme of the solar heating system. The 

selected hydraulic scheme defines the system 

configuration and function. The selection is made from 

systems for DHW heating, central heating backup or 

swimming pool water heating as per the system 

pictographs (➔ 37/1). The settings contain all decisive 

temperatures, temperature differentials, pump speeds 

and optional functions, e.g. tube collector functions, 

capturing the heat amount, cylinder water transfer, 

daily heating of the pre-heating volume, Double- 

Match-Flow etc. required for the system operation. The 

marginal conditions for controlling two collector 

arrays with different orientation and heating the 

cylinder via an external heat exchanger are also 

entered here. 

The SC40 further provides the following extensions via 

the control facilities of the SC20 solar control unit: 

● Central heating backup with buffer bypass 

actuation 

● Swimming pool water heating using a plate-type 

heat exchanger 

● Actuation of a 2nd consumer via a pump or threeway 

diverter valve 

● Actuation of a water transfer pump with cylinders 

connected in series 

● East/west control for separate operation of two 

collector arrays 

● Daily heating of pre-heating cylinder for 

pasteurisation purposes 

36 

● Integral capturing of the heat amount with flow 

meter 

● Cylinder heating via an external heat exchanger 

● Data transfers via an RS232 interface 

● Collector array cooling for reducing stagnation 

times 

● Rapid diagnosis and simple function tests 

Detailed descriptions of special functions ➔ page 41 ff. 


Caption 

1 System pictograph 

2 Segment LCD 


4 Function key "OK" 

5 Direction key "Back" 


1 

2 

3 

4 

5


Logamatic SC40 solar control unit, system and function overview 

Hydraulic 

no. 

Domestic hot water heating 

T1 

T2 

T3 

T4 

T5 

T6 

T7 

WMZ 

S8 

WMZ 

S8 

WMZ 

R1 

R1 

S1 

S7 

System pictograph Selectable additional functions, subject to the hydraulic scheme 

S1 

S7 

S1 

WMZ 

S5 

R1 WMZ S8 R5 

S8 

WMZ 

S8 

WMZ 

S8 

R1 

R1 

R1 

R1 

S1 

S7 

S7 

S1 

S7 

S7 

S1 

S1 

S6 

R5 

S6 

S5 

S5 

R4 

R2 

S7 

S8 

R2 

R2 

S6 

S3 

S4 

R5 

S3 

S2 

S3 

S4 

S3 

S4 

R2 S2 

S2 

S3 

S4 

R2 S2 

Double-Match- 

Flow 

● 

(S4) 

● 

(S4) 

● 

(S4) 

● 

(S4) 

● 

(S3) 

● 

(S3) 

● 

(S3) 

Cooling 

function 

● 

(S1, S2) 

● 

(S1, S2, S5) 

● 

(S1, S2) 

● 

(S1, S2, S5) 

● 

(S1, S2) 

● 

(S1, S2, S5) 

● 

(S1, S2) 

37/1 Logamatic SC40 solar control unit, system and function overview 

Symbols: ● Function available, – function unavailable, (S..) required temperature sensors 

R3 

R3 

S2 S4 

S3 

R3 

S2 S4 

S3 

R3 

S2 S4 

R3 

R3 

R3 

Daily heating Heat exch. antiicing 

protection 

● 

(S2, S3) 

● 

(S2, S3) 

● 

(S2, S3) 

● 

(S2, S3) 

● 

(S2, S3, S4) 

● 

(S2, S3, S4) 

● 

(S2, S3, S4) 


– 

– 

● 

(S6) 

● 

(S6) 

– 

– 

● 

(S6) 


37

2 


38 

Hydraulic 

no. 

T8 

Central heating backup 

H1 

H2 

H3 – 

H4 – 

H5 

H6 

R1 

WMZ 

R1 

WMZ 

S8 

R1 

WMZ 

S8 

WMZ 

S8 

S1 

S8 

R1 

S7 

R1 


S5 

S1 

S7 

R4 

WMZ 

S8 

S1 S555 

S7 

WMZ 

S8 

R4 

R1 

S1 

S1 

S1 

S7 

S7 

S5 

R4 

S6 

R5 

R2 

S4 

S2 

S4 

S6 

S2 

R2 

S7 

R3 

S3 

R2 

S4 

S6 

S2 

S4 

S6 

S2 

R2 S2 

S6 

WMZ 

S8 

R4 S5 

R1 

R2 

S1 

S7 

S4 

S2 

S6 

S4 

S6 

S5 

R3 

Double-Match- 

Flow 

● 

(S3) 

● 

(S4) 

● 

(S4) 

● 

(S4) 

● 

(S4) 

Cooling 

function 

● 

(S1, S2, S5) 

● 

(S1, S2) 

● 

(S1, S2, S5) 

● 

(S1, S2) 

● 

(S1, S2, S5) 

● 

(S1, S2, S5) 

● 

(S1, S2, S5) 



R3 

S2 S4 

R5 

R3 

R5 

R5 

R5 

S3 

R5 

R5 

S3 

S3 

S3 

S3 

S3 

● 

(S2, S3, S4) 



protection 

● 

(S6) 

– – 

– – 

– 

– 

● 

(S2, S4) 

● 

(S2, S4) 

● 

(S7) 

● 

(S7) 

– 

–

Hydraulic 

no. 

H7 – 

H8 – 

H9 WMZ 

S2 

– 

H10 

H11 

H12 

WMZ 

R1 

S8 

R1 

S1 S5 

WMZ 

S1 

S7 

S8 

S8 R1 

R1 

WMZ 

R1 

H13 – 

R1 

R1 

WMZ 

R4 



S7 

R2 

R4 

S1 

S7 

S1 

S7 

R4 

S2 

S4 

R3 

S4 

R3 

WMZ 

S8 R4 

S1 S5 

S8 

WMZ 

S1 

S7 

S8 

S1 S5 

S8 

S7 

S7 

R4 

R3 

R2 

S2 

R2 

S6 

S2 

R4 

S2 

S6 

R5 

R4 

S5 

R2 

S6 

S5 

S6 

S2 

S2 

S6 

R5 

R2 

S6 

S4 

S6 

S5 

S3 

S4 

S3 

Double-Match- 

Flow 

● 

(S6) 

● 

(S6) 

● 

(S5) 

Cooling 

function 

● 

(S1, S2, S4, S5) 

● 

(S1, S2, S5) 

● 

(S1, S2, S5) 

● 

(S1, S2, S4) 

● 

(S1, S2, S4, S5) 

● 

(S1, S2, S3) 

● 

(S1, S2, S3, S5) 



S4 

R3 

R3 

S4 

S3 

S4 

R2 

S3 

R3 

R5 

R5 

R5 

R3 

S3 

S3 

S3 


protection 

● 

(S2) 


– 

– 

● 

(S2) 

● 

(S2) 

● 

(S2) 

– 

– 

● 

(S4) 

● 

(S4) 

– 

– 

● 

(S6) 

● 

(S6) 


39

2 


Swimming pool water heating 

40 

Hydraulic 

no. 

S1 

S2 

S3 – – – 

S4 – – – 

● 

(S4) 

● 

(S4) 


– 

– 

● 

(S2, S4) 

● 

(S2, S4) 

S5 S3 

– – – 

S6 

WMZ 

R1 

WMZ 

S8 

R1 

WMZ 

S8 

WMZ 

S8 

S1 

S1 

S7 


S4 

S2 

S6 

S8 R4 R5 R2 

R1 

R4 

S7 

S1 

S7 

S5 

S1 

S7 

R3 

S6 

R5 

S4 

R2 

S3 

S4 

S2 

S3 

Double-Match- 

Flow 

● 

(S4) 

Cooling 

function 



R3 

S2 

S6 

S3 

R4 R5 R2 

S2 

S4 

R1 WMZ 

S8 

R4 R3 R2 

R1 

R4 

S1 

S7 

S1 

S7 

S4 

S2 

S2 

S4 

S6 

R3 

S6 

S5 

R5 

S6 

R5 

S5 

R2 

S3 

R1 WMZ R4 R5 R3 S5 

S8 

R2 

S3 

R3 

– – 


protection 

● 

(S6) 

● 

(S6) 

● 

(S6) 

● 

(S4) 

● 

(S4) 

● 

(S6)

2.3.4 Special functions 

Central heating backup via buffer bypass circuit 

The solar central heating backup can be controlled 

with the FM443 solar function module and the SC40 

solar control unit via a buffer bypass circuit using the 

HZG kit (➔ 41/1) available as an accessory. A buffer 

bypass circuit provides a hydraulic connection 

between the thermal store and the heating circuit 

return. If the temperature in the thermal store is higher 

than the heating circuit return temperature by an 

adjustable amount (ϑOn), the three-way diverter valve 

opens in the direction of the thermal store. The thermal 

store heats the return water that is flowing to the 

boiler. If the temperature differential between the 

thermal store and the heating circuit return drops by 

an adjustable amount (ϑOff ), the three-way diverter 

valve switches in the direction of the boiler and stops 

cylinder discharging. 

The operating status of the three-way diverter valve is 

displayed by the FM443 solar function module and the 

SC40 solar control unit. The HZG kit includes: 

● Two FSS temperature sensors (NTC 10 K, Ø9.7 mm, 

3.1 m lead) for connecting to the FM443 or SC40 

● One three-way diverter valve 

(threaded connection Rp1") 


1 Cylinder temperature sensor (two sensors provided in the 

HZG kit; available as sensor kit for the 2nd consumer FSS) 

2 Three-way diverter valve (included in HZG kit; available separately 

as diverter valve for the 2nd consumer VS-SU) 


Δp3WV Pressure drop of three-way diverter valve (HZG kit or VS-SU) 

VR Heating system return flow rate 


41/1 HZG kit with three-way diverter valve and two cylinder 

temperature sensors 

Δp3WV 

mbar 

41/2 Pressure drop of three-way diverter valve (➔ 41/1) 


400 

300 

200 

100 

0 

1000 2000 

I 

3000 4000 5000 

VR h 

2 

1 

41

2 


Solar heating systems with two consumers 

Two solar consumers (cylinders) can be heated using 

the FM443 solar heating function module and the 

SC40 solar control unit in combination with the sensor 

kit 2nd consumer FSS and the diverter valve 2nd 

consumer VS-SU. 

The single-line solar station KS01...E can be used as an 

alternative to the VS-SU. Priority is given to the first 

consumer (selectable with the SC40). If the 

temperature differential setting of 10 K is exceeded, the 

solar control unit switches on the supply pump in solar 

heating circuit 1 (high-flow/low-flow operation with 

thermosiphon cylinder ➔ page 28). 

The solar control unit optionally changes over to an 

additional solar circuit pump or the second consumer 

via a three-way diverter valve, if: 

● The first consumer has reached the maximum 

cylinder temperature or 

● The temperature spread in solar circuit 1 is no longer 

adequate for heating the first consumer, in spite of 

using the slowest pump speed. 

42 

FSW1 

FV 

FSK 

V 

WMZ 

ZV 

VS- 

SU 

Twin- 

Tube 

R 

WMZ 

1.2 

MAG 

FSW2 

FR 

Logasol 

SKN3.0 

SKS4.0 

Logasol 

KS01.. 

FE 

AW 

FSS1 

WWM 

AW 

Logalux SM... 

VS 

RS 

EK 

FE 

PS 

FSX 

FSS2 

Heating of the second consumer is interrupted every 30 

minutes to check the temperature rise in the collector. 

If the collector temperature increases by more than 1 K 

per minute, the check is repeated until: 

● The temperature increase at the collector 

temperature sensor is less than 1K per minute, or 

● The temperature spread in solar circuit 1 will enable 

heating of the prioritised consumer again 

The solar function module FM443 and solar control 

unit SC40 indicate which consumer is currently being 

heated. The following are required as accessories for a 

second consumer: 

● diverter valve for 2nd consumer VS-SU: Three-way 

diverter valve (threaded connection Rp1") 

● Alternative: Single-line solar station KS01... E 

● Sensor kit for 2nd consumer FSS: 

Cylinder temperature sensor as sensor FSS2 


42/1 Solar heating system with flat-plate collectors for two consumers with control via solar function module FM443 (abbreviations ➔ page 148; 

additional sample systems ➔ page 60 ff.) 

VK 

MAG 


HZG 

A B 

AB 

RK 

VK 

RK 

Logalux PL... Logano EMS 

Oil/Gas 

Logamatic 4121 

+ FM443 

1 

2

Heat meter kit WMZ 1.2 (accessory) 

The solar function module FM443 and solar control 

unit SC40 include the function of a heat meter. If heat 

meter kit WMZ 1.2 is being used, the amount of heat 

can be captured directly by the solar circuit taking the 

glycol content into consideration (adjustable from 0% 

to 50%). The amount of heat and the current output in 

the solar heating circuit (only with FM443) as well as 

the flow rate can be monitored this way. 

The WMZ 1.2 kit includes: 

● Flow meter with two threaded 6" water meter 

connections 

● Two temperature sensors as pipe contact sensors 

with clips for attaching to flow and return 

(NTC 10 K, Ø9.7 mm, 3.1m lead) for connecting to 

FM443 or SC40 

Because of the differing nominal flow rates there are 

three different WMZ 1.2 heat meter kits: 

● For a maximum of five collectors 

(nominal flow rate 0.6 m3 /h) 

● For a maximum of ten collectors 

(nominal flow rate 1.0 m3 /h) 

● For a maximum of fifteen collectors 

(nominal flow rate 1.5 m 3 /h) 

The flow meter must be installed in the solar return. 

The contact sensors can be attached to the flow and 

return using clips. 

The pressure drop of the three-way diverter valve and 

the flow meter must be taken into consideration when 

the complete stations are selected (➔ 41/2 and 43/2). 



1 Threaded water meter connection 6" 

2 Flow meter 

3 Contact temperature sensor 


a WMZ1.2 up to 5 collectors 

b WMZ1.2 up to 10 collectors 

c WMZ1.2 up to 15 collectors 

ΔpWMZ Flow meter pressure drop 

VSol Solar circuit flow rate 


110 

208 

43/1 Heat meter kit WMZ 1.2 (dimensions in mm) 

43/2 Pressure drop of WMZ1.2 flow meter 

1 

2 

3 

43

2 


Two collector arrays with different orientation (east/west control) 

If insufficient space is available on a rooftop, select the 

system hydraulics of the east/west orientation. The 

collectors are distributed on two rooftops, which makes 

special demands of the hydraulic scheme and the 

control system. 

FSK 

The hydraulic system should preferably be 

implemented using two solar stations (a 2-line station 

and a 1-line station). The advantage is that both 

collector arrays can be operated at the same time at 

PSS 

midday. 

The circuits must be controlled separately when 

WMZ 

FSW1 

operating with two solar stations, which is taken care 

of by the SC40 solar control unit. 

FSW2 

Solar cylinder heating via an external heat exchanger 

These system hydraulics are chosen if a relatively small 

solar heating cylinder with high DHW usage is being 

used with a relative large collector area, or only a 

shared heat transfer is to be implemented with several 

solar heating cylinders (thermal stores). In both cases, 

a high heat exchanger output is required that cannot 

be provided by the indirect coils that are integrated 

inside the cylinders. 

From a hydraulic point of view, another pump is 

required at the secondary side of the heat exchanger 

that has to be controlled. This function can be 

performed by the SC40 solar control unit. 

A good hydraulic balance is required between the 

primary and secondary sides of the heat exchanger 

with this hydraulic scheme. 

44 

44/1 East/west control via two solar stations 



FSS Cylinder temperature sensor (bottom) 

FSX1 Cylinder temperature sensor (top; optional – required for 

water transfer) 

FSX2 Cylinder temperature sensor (centre; optional – required for 

Double-Match-Flow function) 

FSW1 Heat meter temperature sensor, flow (option) 

FSW2 Heat meter temperature sensor, return (option) 

PSS Solar circuit pump 

PUM Water transfer pump (option) 

WMZ Heat meter kit 



FSS Cylinder temperature sensor (bottom) 

FSX1 Cylinder temperature sensor (top; option – required for 

water transfer) 

FSX2 Cylinder temperature sensor (centre; option – required for 

Double-Match-Flow function) 

WT Sensor for heat exchanger, external 

FSW1 Heat meter temperature sensor, flow (option) 

FSW2 Heat meter temperature sensor, return (option) 


PWT Heat exchanger pump 

PUM Water transfer pump (option) 

SU Diverter valve 

WMZ Heat meter kit 


FSK 

FSW1 WT 

FSK 

PSS 

PSS PWT 

WMZ 

FSW2 

SU 

FSX1 

FSX2 

FSX1 

FSX2 

FSS 

FSS 

44/2 Control unit for heating a cylinder via an external heat 

exchanger 

PUM 

PUM

Cylinders connected in series 

When cylinders are connected in series, the preheating 

cylinder is heated via the solar heating system. 

The solar heating function module FM443 or solar 

control unit SC40 is used to control the solar heating 

system. 

When hot water is drawn-off, the water that has been 

pre-heated using solar energy enters the cold water 

inlet of the standby cylinder via the hot water outlet of 

the pre-heating cylinder and is reheated by the boiler, 

if required (➔ 45/1). 

With high levels of solar yield, the pre-heating cylinder 

can also achieve higher temperatures than the 

standby cylinder. To enable the use of the entire 

cylinder volume for solar heating, a pipe must be 

routed from the hot water outlet of the standby 

cylinder to the cold water inlet of the pre-heating 

cylinder. A pump is used to deliver the water in such 

cases. 

To safeguard that the system is operated in accordance 

with the technical regulations in DVGW Code of 

Practice W 551 (➔ 59/1), all water in the pre-heating 

stages must be heated to 60 °C once every day. The 

temperature in the standby cylinder must always be 

≥ 60 °C. The daily heating of the pre-heating stage can 

FSK 

PSS 

SP1 

Collector 

Logasol 

KS01.. 

TW 

FSS 

System part-heated 

by solar energy 

(pre-heat stage) 

VS 

M 

RS 

AW 

Pre-heat cylinder 

Logalux SU... 

EK 


DHW heating 

(downstream) 

be carried out either in standard operation by solar 

heating or via conventional reheating. 

In combination with the SC40 solar control unit, two 

additional cylinder sensors are needed that are 

installed at the top or bottom of the standby cylinder. 

Cylinders with insulation that can be removed allow 

the sensor to be freely secured with straps. The FSX 

sensor is installed inside the standby cylinder. 

The control units FM443 or SC40 monitor the 

temperatures via the sensor in the pre-heating 

cylinder. If the required temperature of 60 °C in not 

achieved in the pre-heating cylinder using solar 

energy, circulation pump P UM between the hot water 

outlet of the standby cylinder and the cold water inlet 

of the pre-heating stage is started during a period when 

no hot water is drawn off (preferably at night). The P UM 

pump remains on until the required temperature has 

been achieved at both sensors or the end of the 

specified period is reached. 

45/1 Example of a DHW pre-heating cylinder and standby cylinder connected in series, control of cylinder water transfer and 

pasteurisation circuit in accordance with DVGW Code of Practice W 551, controlled by a FM443 

(example system ➔ 88/1; abbreviations ➔ page 148) 


FSX 

PS 

VS 

M 

RS 

P UM 

AW 

EZ 

WWM 

EK 

Standby cylinder 

Logalux SU... 

PZ 

FK 

Boiler Logano EMS 

Oil/Gas 

1 

2 

Logamatic 

4121 

+ FM443 

45

2 


2.4 Logasol KS... complete station 


● An assembly consists of all required components 

such as the solar circuit pump, the gravity brake, the 

safety valve, the pressure gauge, a ball valve in the 

flow and return with integral thermometer, a 

throughput limiter and thermal protection. 

● Available as 1-line or 2-line solar station. 

● Four different output stages 

● Optionally available with or without integral 

control unit 

Max. 

recommended no. 

of collectors 

Logasol KS01... complete stations are designed for one 

solar consumer. However, they are suitable for two 

consumers if a 2-line solar station is operated in 

combination with a 1-line solar station. This 

arrangement provides two separate return connections 

with separate pumps and throughput limiters (➔ 47/2). 

This enables the hydraulic balancing of two consumers 

with different pressure drop values. One safety 

assembly is sufficient for this arrangement, provided 

that no pressure filling is required. 

The two-consumer system is controlled either by an 

FM443 solar function module or an SC40 solar control 

unit in combination with the 2nd consumer sensor kit 

FSS. Optionally, the SC40 can also already be installed 

in the solar station. 

As an alternative to the 1-line station, a VS-SU 2nd 

consumer diverter valve can also be used. 

Another application for the combination of a 2-line 

solar station with a 1-line solar station is the 

implementation of a solar heating system with two 

collector arrays in different orientation (east/west 

control). Here too it is important to have two separate 

return connections with separate pumps and 

46 

Without integral 

control unit 

Configuration of the Logasol KS01.. complete 

station 

Two versions and four different output levels of the 

Logasol KS01... complete station are available for 

optimum adaptation to the collector array. 

The 2-line solar stations for collector arrays with up to 

50 collectors are already equipped with an air 

separator. The smallest version KS0105 is also 

available with an integral SC20 or SC40 solar control 

unit or with the SM10 solar module. 

1-line complete stations without air separators offer a 

solar circuit pump and shut-off valves for the 

additional return line in systems with two collector 

arrays (east/west) or two consumers. 

The table 46/1 shows the different versions and 

recommends the maximum number of collectors that 

can be operated with them. A pipework calculation is 

required to determine the correct output level. 

SM10 

With integral 

control unit 

SC20 SC40 

throughput limiters (➔ 47/2). As previously described, 

hydraulic balancing of the two collector arrays with 

different pressure drop values is now feasible. Two 

safety assemblies (part of the standard delivery) and 

two diaphragm expansion vessels (MAG) are required 

for this arrangement. 

Two collector arrays with different orientation are 

controlled using an SC40 solar control unit in 

combination with an additional collector array 

temperature sensor. Here too, a 2-line solar station 

with integrated SC40 solar control unit can be used. 

The Logasol KS01... complete station without integral 

control unit is specially designed for combination with 

solar function modules that are integrated into the 

boiler control unit. These include function modules 

FM244, FM443 and SM10. 

The Logasol KS01.. complete station SM10 is connected 

to the Logamatic EMS control system via a BUS line, 

enabling an intelligent combination of the boiler 

control and solar heating control units. 


With integral air 

separator 

5 Logasol KS0105 E – – – – 

10 Logasol KS0110 E – – – – 

5 Logasol KS0105 Logasol KS0105SM10 Logasol KS0105SC20 Logasol KS0105SC40 ● 

10 Logasol KS0110 – – – ● 

20 Logasol KS0120 – – – ● 

50 Logasol KS0150 – – – ● 1) 

46/1 Selection of a suitable Logasol KS... complete station subject to the number of collectors and their equipment level 

Symbols: ● Integral, – not integral 

1) Additional air separator at the roof level required for each collector array

➔ The essential diaphragm expansion vessel (DEV) is 

not part of the standard delivery of the Logasol KS... 

complete station. It must be sized for each individual 

case (➔ page 110 ff.). An AAS/Solar connection kit with 

corrugated stainless steel pipe, a ¾" quick release 

coupling and a wall retainer for a DEV with a 

2 

1 

10 

9 

2 

V 

V 

1 

47/1 Layout of the Logasol KS01... complete station without integral 

solar control unit 

2 

1 

3 

4 

5 

6 

7 

10 

6 

8 

2 

2 

R 

R 


3 

4 

5 

6 

7 

6 

2 

8 

maximum of 25 l are available as accessories. The wall 

retainer cannot be used for DEV with a capacity of 35 l 

to 50 l. The AAS/Solar connecting kit is unsuitable for 

DEV with a capacity in excess of 50 l because the DEV 

connection is larger than ¾". 

Caption (➔ 47/1 and 47/2) 

V Flow from collector to consumer 

R Return from consumer to collector 

1 Ball valve with thermometer and integral gravity 

brake 

Position 0° = gravity brake ready for operation, 

ball valve open 

Position 45° = gravity brake manually open 

Position 90° = ball valve closed 

2 Clamping ring fitting (all flow and return connections) 

3 Safety valve 

4 Pressure gauge 

5 Connection for diaphragm expansion vessel 

(DEV and AAS/Solar not part of the standard delivery) 

6 Fill & drain valve 

7 Solar circuit pump 

8 Throughput indicator 

9 Air separator (not with 1-line solar stations) 

10 Regulating/shut-off valve 

Dimensions and specification ➔ 48/1 and 48/2 

47/2 Layout of the combination of Logasol KS01... 2-line complete station and Logasol KS01... 1-line complete station E 

R 

R 

V 

V 


1 

2 

R 

R 

3 

4 

5 

6 

7 

6 

9 

2 

8 

47

2 


Dimensions and specification of Logasol KS… complete station 

48/1 Dimensions of the Logasol KS... complete station 

Logasol complete station KS0105 E KS0110 E KS0105 KS0110 KS0120 KS0150 

Number of consumers 1 1 1 1 1 1 

Casing dimensions Height H mm 355 355 355 355 355 355 

Selecting the Logasol KS... complete station 

Information concerning the selection of a suitable 

complete station ➔ page 109. 

48 

Logasol 

KS01... E 

Width W mm 185 185 290 290 290 290 

Depth D mm 180 180 235 235 235 235 

Detailed dimensions A mm – – 130 130 130 130 

Copper pipe connection size 

(clamping ring fitting) 

B 

C 

C mm 93 93 80 80 80 80 

E mm 50 50 50 50 50 50 

Flow/ 

return 

mm 15 × 1 22 × 1 15 × 1 22 × 1 28 × 1 28 × 1 

Expansion vessel connection 6" 6" 6" 6" 6" 1" 

Safety valve bar 6 6 6 6 6 6 

Circulation pump Type 

Finished 

length 

Grundfos 

Solar 

15-40 

H 

Logasol 

KS01... 

Grundfos 

Solar 

15-70 

Grundfos 

Solar 

15-40 

Grundfos 

Solar 

15-70 


Grundfos 

UPS 

25-80 

Grundfos 

Solar 

25-120 

mm 130 130 130 130 180 180 

Electrical power supply VAC 230 230 230 230 230 230 

Frequency Hz 50 50 50 50 50 50 

Max. power consumption W 60 125 60 125 195 230 

Max. current strength A 0.25 0.54 0.25 0.54 0.85 1.01 

Throughput limiter adjusting range l/min 0.5–6 2–16 0.5–6 2–16 8–26 20–42.5 

Weight kg 5.4 5.4 7.1 (8.01) ) 7.1 9.3 10.0 

48/2 Specification and dimensions of the Logasol KS… complete station 

1) Logasol KS0105 complete station with integral SC20, SC40 or SM10 control unit 

B T 

A C E 

Logasol 

KS01... E 

KS01...

2.5 Other system components 

2.5.1 LA1 air separator for a 1-line complete station 

The LA1 air separator is used for filling the solar 

heating system with the BS01 filling station 

(➔ page 120). The LA1 separates residual trapped air 

(micro-bubbles) during operation and ensures that the 

solar heating circuit is continuously de-aerated. The 

AAV at the highest point of the system is not required. 

The LA1 is installed in the solar heating circuit using 

clamping ring fittings. Two connection sizes are 

available: 

● LA1 Ø18 

● LA1 Ø22 

2.5.2 Connection with Twin-Tube 

Twin-Tube is a thermally insulated twin tube with UV 

protective jacket and integral sensor lead. The 

connection kits contains suitable fittings for the 

various collector types to enable the Twin-Tube 15 and 

Twin-Tube DN20 fittings to be connected to the 

collector array, the complete station and the cylinder. 

An appropriate mounting kit for the Twin-Tube special 

tube consisting of four oval clips with headless spiral 

screws and dowels must be ordered separately. 

Space for a bending radius of at least 110 mm for routing 

the Twin-Tube 15 must be available on site (➔ 49/2). 

The corrugated stainless steel Twin-Tube DN20 can be 

bent at an angle of up to 90° without springing back. 


49/1 Air separator 

r ≥ 110 

r ≥ 110 

49/2 Bending radius for Twin-Tube 15; sizes in mm 

(dimensions ➔ 49/3) 

Twin-Tube 15 (DN12) DN20 

Dimensions (➔ 49/2) A mm 73 105 

B mm 45 62 

Pipe material Soft copper (F22) in accordance with 

DIN 59753 


A 

Corrugated stainless steel pipe 

no. 1.4571 

Pipe dimensions Diameter DN 2 ×15 × 0.8 2 × DN20 (external Ø = 26.6 mm) 

Length m 12.5 12.5 

Insulating material EPDM rubber EPDM rubber 

Fire protection class DIN 4102-B2 DIN 4102-B2 

λ insulation W/m·K 0.04 0.04 

Insulation thickness mm 15 19 

Temperature resistant up to °C 190 190 

Protection film PE, UV-resistant PE, UV-resistant 

Sensor lead 2 × 0.75 mm 2 , VDE 0250 2 × 0.75 mm 2 , VDE 0250 

49/3 Twin-Tube specification 

B 

49

2 


2.5.3 Overvoltage protection for the control unit 

The collector temperature sensor in the lead collector 

can be subject to overvoltage during a thunderstorm 

because of its exposed location on the roof. This 

overvoltage can destroy the sensor. 

The overvoltage protection is not a lightning 

conductor. It is designed for situations where lightning 

strikes somewhere in the vicinity of the solar heating 

system can cause overvoltages. Safety diodes limit this 

overvoltage to a level that will not damage the control 

unit. The junction box must be located within the 

range of the lead length of the FSK collector 

temperature sensor (➔ 50/1). 

2.5.4 Solar fluid 

The solar heating system must be protected against 

frost. Either solar fluid L or Tyfocor LS antifreeze can be 

used for this purpose. 

Solar fluid L 

Solar fluid L is a ready-made mixture consisting of 50% 

PP glycol and 50% water. This clear mixture is foodcompatible 

and biologically degradable. 

Solar fluid L protects the system against frost and 

corrosion. As can be seen in the diagram 50/2, solar 

fluid L provides frost protection down to an outside 

temperature of –37 °C. In systems with Logasol SKN3.0 

and SKS4.0 collectors, solar fluid L ensures a reliable 

operation at temperatures from –37 °C to +170 °C. 

50 

50/1 Overvoltage protection for control unit (sample installation) 


ϑ A Outside temperature 


V 

ϑ A 

˚C 

V 

FSK 

SP1 

0 

–10 

–20 

–30 

–37 

R 

Logasol 

SK... 

Twin-Tube 

Logasol 

KS0105SC.. 

R 

MAG 

230 V 

50 Hz 

E Automatic all-metal air 

vent valve (accessory) 

FSK Collector temperature 

sensor (standard delivery 

of the control unit) 

KS01… Logasol KS… complete 

station with integral 

control unit 

SK… Logasol SKN3.0 or 

SKS4.0 solar collector 

SP1 Overvoltage protection 

Solar fluid L 


–50 

0 10 20 30 40 50 

PP: glycol/% by vol. 

50/2 Level of frost protection of heat transfer medium subject to the 

glycol:water mixture 

60

Tyfocor LS 

Tyfocor LS is a ready-made mixture consisting of 43% 

PP glycol and 57% water. The mixture is foodcompatible, 

biologically degradable and has a 

red/pink colour. 

Tyfocor LS protects the system against frost and 

corrosion. As can be seen in the table 51/1, Tyfocor LS 

provides frost protection down to an outside 

temperature of – 28 °C. In systems with Logasol SKN3.0 

and SKS4.0 collectors, Tyfocor LS ensures a reliable 

operation at temperatures from –28 °C to +170 °C. 

Never dilute the prepared mixture of Tyfocor LS heat 

transfer medium. The values in table 51/1 apply to 

situations where water remaining in the solar heating 

system after flushing has led to prohibited dilution of 

the heat transfer medium. 

➔ Only Tyfocor LS must be used in solar heating 

systems with Vaciosol CPC vacuum tube collectors. 

Testing the solar fluid 

Heat transfer media based on mixtures of propylene 

glycol and water age during operation in solar heating 

systems. This decay can be detected from the outside by 

dark colouration or opaqueness. Long periods of 

overheating (> 200 °C) result in a characteristic 

pungent smell of burning. The fluid becomes almost 

black because of the increase in solid decomposition 

products of the propylene glycol or the inhibitors that 

are no longer soluble in fluid. 

The main influences are high temperatures, pressure 

and the duration of the load. These factors are strongly 

influenced by the absorber geometry. 

Favourable characteristics are obtained using fanshaped 

absorbers such as the ones used in the SKN3.0, 

and double meander absorbers with return line at the 

bottom such as the ones used in the SKS4.0. 


Tyfocor LS 

prepared mixture 

% by vol. 

Value read off 

Glykomat °C 

However, the locations of the connecting pipes on the 

collector also influence the stagnation characteristics 

and therefore the ageing of the solar fluid. It is 

therefore important to avoid running the flow and 

return lines over long distances with inclines at the 

collector array, since solar fluid will run into the 

collector from these line sections in the event of 

stagnation and increase the vapour volume. Ageing is 

also accelerated by oxygen (air-borne) and impurities 

such as copper or iron cinders. 

To check the solar fluid on site, determine the pH value 

and the antifreeze level. Suitable pH measuring sticks 

and a refractometer (frost protection) are included in 

the Buderus solar service case. 


Provides frost 

protection down to 

°C 

100 –23 

Prohibited dilution with water! 

–28 

95 –20 –25 

90 –18 –23 

85 –15 –20 

80 –13 –18 

51/1 Frost protection with Tyfocor LS heat transfer medium 

Ready-mixed solar fluid pH value in the delivered condition pH limit for replacement 

Solar fluid L 50/50 approx. 8 ≤ 7 

Tyfocor LS 50/50 approx. 10 ≤ 7 

51/2 pH limits for checking ready-mixed solar fluid 

51

2 


2.5.5 Thermostatically controlled domestic hot water mixer 

Anti-scalding protection 

If the maximum cylinder temperature is set higher 

than 60 °C, take suitable measures to provide 

protection against scalding. The following options are 

available: 

● Either install a thermostatically controlled DHW 

mixer downstream of the cylinder's DHW 

connection or 

● At all draw-off points, limit the mixing temperature 

using thermostatic valves or pre-selectable monolever 

mixing taps (maximum temperatures of 45 °C 

to 60 °C are considered to be relevant in residential 

buildings) 

The diagram 52/1 must be taken into consideration 

when designing a system with a thermostatically 

controlled DHW mixer. 

➔ The mixed water temperature can be adjusted in 6 

steps of about 5 °C within a temperature range of 35 °C 

to 60 °C. 


Δp Pressure drop of a thermostatically controlled DHWmixer 

V Flow rate 

52 

V 

l/min 

Thermostatic DHW mixer assembly with circulation pump 

The thermostatic DHW mixer assembly is suitable for 

use in detached house or two-family home and for all 

DHW cylinders with an operating temperature up to 

73 

90 °C. It is used to provide protection against scalding, 

particularly for solar DHW systems. 

The DHW mixer assembly consists of a thermostatic 

mixer valve for adjustable temperatures ranging from 

35 °C to 65 °C, a DHW circulation pump, two 

thermometers for the DHW outlet temperature and the 

cylinder temperature, non-return valves and shut-off 

valves in a compact unit. The benefit offered by this 

unit is rapid, fault-free assembly of the DHW mixer 

and the DHW circulation. 

DHW mixer assembly 

Max. operating pressure: bar 10 

Max. water temperature °C 90 

Setting range °C 35–65 

Kvs value m 3 /h 1.6 

52/2 DHW mixer assembly specification 

DHW circulation pump 

Power supply V 230 

Frequency Hz 50 

Power consumption at stage 1 W 27 



52/3 DHW circulation pump specification 

52/1 Pressure drop of a thermostatically controlled DHW mixer at a 

hot water temperature of 80 °C, a mixed water temperature of 

60 °C and a cold water temperature of 10 °C 


30 

20 

10 

5 

40 60 80 100 200 400 600 800 1000 

86.5 

Δp/mbar 

383 

343 

300 

342.5 58 93 

52/4 Dimensions of DHW mixer valve with DHW circulation pump 

(dimensions in mm)

5 

4 

3 

2 

1 

EW 

MIX 

EK 11 EZ 

53/1 Connections and components of DHWmixer assembly 

AW 

EZ 

EK 

A 6 B 

53/2 DHW mixer assembly installation diagram 

4 

3 

1 

MIX 


AW DHW outlet 


EZ DHW circulation inlet 

MIX Mixed water 

1 Non-return valve 

2 DHW circulation pump 

3 Thermostatic mixing valve 

4 Shut-off valve with non-return valve 

5 DHW circulation line 

6 AW draw-off point 

7 Cold water connection in accordance with the technical 

regulations for domestic water installation (TRWI) 

7 

1 

1 

2 


5 

7 

8 

9 

10 

EK 

6 


A Mixed water outlet at draw-off points 

B DHW circulation line inlet from draw-off points 

EK Cold water inlet (mixer assembly) 

EW DHW inlet (mixer assembly) 

EZ DHW circulation inlet to cylinder 

MIX Mixed water 

1 Cold water supply ball valve Rp6" (internal) 

2 Tee with non-return valve 

3 DN20 DHW mixing valve 

4 Dial thermometer 

5 DHW water supply ball valve Rp6" (internal) with non-return 

valve 

6 Mixed water drain ball valve Rp6" (internal) 

7 DHW circulation shut-off valve Rp6" (internal) 

8 DHW circulation pump 

9 Tee with non-return valve 

10 Fem. reducing coupling Ø G1" x Rp6"” 

11 Connecting piece with non-return valve 

53/3 Residual head of the DHW circulation pump 


H Residual head 

V Flow rate 

a Stage 3 

b Stage 2 

c Stage 1 


53

2 


Method of operation in conjunction with a DHW circulation line 

The thermostatically controlled DHW mixer mixes 

sufficient cold water into the hot water from the 

cylinder to prevent the temperature from exceeding a 

selected set temperature. In conjunction with a DHW 

circulation line, a bypass line is required between the 

DHW circulation inlet at the cylinder and the cold 

water inlet into the thermostatically controlled DHW 

mixer (item 2 ➔ 54/1). 

If the cylinder temperature exceeds the set value that 

has been selected at the thermostatically controlled 

DHW mixer and no water is being drawn off, the 

circulation pump delivers part of the DHW circulation 

return via the bypass line directly to the DHW mixer 

cold water inlet, which is now open. The hot water 

from the mixer now mixes with the colder water from 

the DHW circulation return. To prevent natural 

circulation, the thermostatically controlled DHW 

mixer must be installed below the cylinder's DHW 

54 

PZ 

3 

V 

R 

WWM 

2 

3 

FE 

AW 

1 

AW 

EZ 

Logalux SM… 

(Logalux SL…2) 

VS 

RS 

54/1 Example of a DHW circulation line with a thermostatically controlled DHW mixer 

outlet. Where that is impossible, install a heat 

insulating loop or non-return valve at the DHW outlet 

connection (AW). This prevents single-pipe DHW 

circulation losses. Non-return valves must be allowed 

for to prevent incorrect circulation and therefore 

cooling and mixing of the cylinder content. 

➔ DHW circulation causes standby losses. It should 

therefore only be used in widespread DHW networks. 

Using a poorly designed DHW circulation line or DHW 

circulation pump could reduce the net solar yield 

considerably. 

If DHW circulation is to be provided, the content of the 

DHW line must be circulated three times per hour in 

accordance with DIN 1988, preventing a temperature 

drop in excess of 5 K. To retain the temperature 

stratification inside the cylinder, coordinate the flow 

rate and any DHW circulation pump cycling. 


EK 

1 Thermostatic DHW mixer assembly with 

DHW circulation pump 

2 DHW circulation bypass line 

3 Non-return valve 

AW DHW outlet 



FE Fill & drain valve 

PZ DHW circulation pump with time switch 

SM… Dual-mode solar cylinder 

Logalux SM300, SM400 or SM500 

SL…2 Dual-mode thermosiphon cylinder 

Logalux SL300-2, SL400-2 or SL500-2 

(not shown) 

V/R Connections for solar heating system 

VS/RS Reheating connection 

WWM Thermostatically controlled DHW mixer


2.5.6 RW return temperature limiter for central heating backup 

Limiting the return temperature 

A so-called return temperature limiter RW is 

recommended in all systems for central heating 

backup 


● One solar control unit SC10 

(temperature differential control unit) 

● One three-way valve with servomotor 

● Two cylinder temperature sensors: 

NTC 10 K, Ø9.7 mm, 3.1 m lead and 

NTC 20 K, Ø6 mm, 2.5 m lead 

The RW return temperature limiter continuously 

compares the temperature in the heating return with 

the temperature in the thermal store. Subject to the 

return temperature, it directs the heating return flow 

through the thermal store or straight back to the boiler 

(➔ 55/2). The buffer bypass circuit can be realised with 

the HZG-set in conjunction with the FM443 solar 

function module or the Logamatic SC40 solar control 

unit. 

Water connection 

To provide the optimum solar yield, size the heating 

surfaces for the lowest possible system temperature. 

Experience has shown that the lowest system 

temperatures are provided by area heating (e.g. 

underfloor heating system). To prevent unnecessarily 

high return temperatures, all heating surfaces must be 

calibrated in accordance with DIN 18380 (VOB part C). 

Heating surfaces that have not been hydraulically 

calibrated can significantly reduce the solar yield. 


1 Solar control unit SC10 

2 Three-way valve with servomotor 


1 

55/1 Control unit and three-way valve of the RW return temperature 

limiter 

VS1 

RS1 

EK 

EK 

2 

AW 

Logalux P750 S 

VS2 

VS4 

A B 

AW 

WWM 

55/2 Hydraulic connection of an RW return temperature limiter 

using the example of the Logalux P750 S combi cylinder 

(abbreviations ➔ page 148) 

AB 

PS 

SC10 

VK 

RK 

55

2 


2.5.7 Swimming pool water heat exchanger 


● Stainless steel plate-type heat exchanger 

● Removable moulded thermal insulation shells 

● Heat transfer from the heat transfer medium in the solar 

heating circuit to the swimming pool water via liquids 

flowing in countercurrents 

● The connection at the swimming pool end must be 

protected using a check valve and a dirt filter 

Sizing the circulation pump in the secondary circuit 

The primary side flow rate depends on the number of 

collectors. The control unit in the complete station regulates 

both the solar circuit pump (primary) and the swimming 

pool water pump (secondary). The secondary pump must be 

resistant to chlorinated water. The inlet pressure at the inlet 

side must also be taken into consideration. 

➔ A relay is required for the swimming pool water pump if 

the total power consumption exceeds the maximum output 

current of the control unit. 

The circulation pump at the secondary side must be sized in 

accordance with the required flow rate using the following 

formula. 

56/1 Secondary pump flow rate 

Calculating parameters (➔ 56/1) 

m SP Secondary pump flow rate in m 3 /h 

n Number of solar collectors 

56 

m SP 

= 

n ⋅ 0.25 

Dimensions and specification of swimming pool water 

heat exchanger 

The swimming pool heat exchanger should be linked in 

parallel to the conventional heating system. This allows the 

solar heating system to heat the swimming pool water either 

alone or with boiler backup. 

56/2 Swimming pool water heat exchangers SWT6 and SWT10 

(specification ➔ 56/3) 

Swimming pool water heat exchanger SWT6 SWT10 

Length L mm 208 208 

Width W mm 78 78 

Depth D mm 55 79 

Max. number of collectors 6 10 

Connections Flow (V) and return (R) inch G6 (male) G6 (male) 

Max. operating pressure: bar 30 30 

Pressure drop at the secondary side 

at a flow rate of 

Weight (net, approx.) kg 1.9 2.5 

Heat exchanger output at temperatures of 

kW 

7 

12 

primary side 

°C 

48/31 

48/31 

secondary side 

°C 

24/28 

24/28 

56/3 Specification for swimming pool water heat exchangers SWT6 and SWT10 

mbar 

m 3 /h 


L 

160 

1.5 

B 

T 

R2 

V2 

V1 

R1 

210 

2.6

3 Notes regarding solar heating systems 

3.1 General information 

Notes regarding solar heating systems 3 

57/1 Specimen wiring diagram in connection with the general information regarding solar heating systems (abbreviations ➔ page 148) 

Item System 

components 

General design infomration 


Further 

information 

1 Collectors The size of the collector arrays must be determined independently of the hydraulic system. ➔ page 80 ff. 

2 

3 

FSK 

2 

3 

PSS 

FP 

FSS 2 

FPU 

Pipework with 

incline to the air 

vent valve 

(Logasol KS…) 

Connection lines 

Twin-Tube 

4 Complete station 

SP1 

VS-SU 

5 

4 

6 

Collector 

Logalux PL... 

57/2 General information regarding solar heating systems 

1 

M1 

M3 

Logasol 

KS01.. 

M4 

VS 1 

VS 2 

VS 3 

RS2 

RS3 

RS 1 

HSM-E 

10 

13 

A M B 

AB 

FR 

HK1 

11 

PH 

M 

FK 

PH 

14 

Logamatic 

2114 

Solid fuel boiler 

Logano S151 


Oil/Gas 

AW 

VS 2 

Logalux SM.../SL... 

Install an all-metal air vent valve at the highest point of the system if the system is not vented 

with "filling station and air separator" or the KS0150 complete station is used (collector 

accessories in Heating Technology catalogue). An air vent valve can also be installed wherever 

the pipework changes direction and goes downwards, and then rises again. The 2-branch 

complete station is equipped with an air separator. 

To make the connecting lines easier to install, the double copper tube Twin-Tube 15 or the 

stainless steel corrugated tube Twin-Tube DN20 is recommended, complete with heat and UV 

protection jacket and integral extension lead for the FSK collector temperature sensor. 

If Twin-Tube cannot be used or larger pipework cross-sections or lengths are required, install 

appropriate pipework and sensor lead extensions on site (e. g. 2 × 0.75 mm 2 ). 

The Logasol KS... complete station contains all important hydraulic and control components 

for the solar circuit. 

The choice of complete station is subject to the number of consumers, the 

number/arrangement of collectors or connections, and the collector array pressure drop. A 

Logasol KS... complete station without control unit is recommended if the solar circuit control 

can be integrated into the boiler control unit via the FM244, SM10 or FM443 solar function 

module or the SC20 or SC40 solar control unit for wall mounting. 

TW 

9 

12 

FSX 

FSS1 

9 

PS 

TW 

M1 

RS 2 

VS 1 

M2 

RS 1 

6 

1 

2 

EZ 


+ FM443 

WWM 

EK 

This diagram is only a schematic 

representation that provides a 

guide to possible hydraulic schemes. 

Implement all safety equipment 

in accordance with local regulations. 

7 

PZ 

8 

➔ page 119 f. 

➔ page 49 f. 

➔ page 108 

➔ page 118 f. 

➔ page 46 ff. 



57

3 

Notes regarding solar heating systems 

Item System 

components 

5 

58 

Diaphragm 

expansion vessel 

General design information 

Size the diaphragm expansion vessel separately subject to the system volume and the safety 

valve response pressure so that it can withstand the volume fluctuations in the system. With 

east/west systems an additional diaphragm expansion vessel is required for the 2nd collector 

array. If the Vaciosol CPC vacuum tube collectors are used, install the diaphragm expansion 

vessel 20-30 cm above the complete station. A pre-cooling vessel is also required if the DHW 

heating coverage is above 60% or in central heating backup systems. 


Further 

information 

➔ page 110 ff 

. 

➔ page 116 f. 

6 DHW cylinder Determine the size of the cylinders independently of the hydraulic system. ➔ page 80 ff. 

7 Hot water mixers 

8 

9 

DHW water 

circulation 

Conventional reheating 

(boiler control unit) 

10 Thermal store 

11 

12 

13 

Heating surface 

sizing and 

adjustment 

Control unit 

Heating circuit 

Return temperature 

controller 

14 Solid fuel boiler 

58/1 General information regarding solar heating systems 

Reliable protection from excessive hot water temperatures (risk of scalding!) is provided by a 

thermostatically controlled hot water mixer (WWM). 

To prevent natural circulation, install the thermostatically controlled DHW mixer below the 

cylinder's DHW outlet. If this is not possible, provide a heat insulating loop or a non-return 

valve. 

A DHW circulation line was not depicted! DHW circulation causes standby losses. It should 

therefore only be used in widespread DHW networks. Using a poorly designed DHW 

circulation line or DHW circulation pump could reduce the net solar yield considerably. 

If DHW circulation is to be provided, the content of the DHW line must be circulated three 

times per hour in accordance with DIN 1988, preventing a temperature drop in excess of 5 K. 

To retain the temperature stratification inside the cylinder, coordinate the flow rate and any 

DHW circulation pump cycling. 

The hydraulic integration of the heat source and the solar control unit that can be used are 

subject to the boiler type and the control unit that is used. 

A distinction can be drawn between the following boiler groups. 

Wall mounted with EMS: e.g. Logamax plus GB142 and GB152 

Floorstanding with EMS: e.g. Logano G125, G135 and G144 

Wall mounted: e.g. Logamax plus GB142 

Floorstanding: e.g. Logano G125, G225, S125, S325, G134 and G234 

Only heat from the solar heating system and (if available) other sustainable energy sources 

should be fed to the buffer part for central heating in the combi cylinder or thermal store. If 

the buffer area of the solar cylinder is heated by a conventional boiler, this part is blocked for 

energy consumption by the solar heating system. 

When the central heating is being integrated, size the radiators such that the return 

temperature is as low as possible. 

As well as sizing the radiators, pay special attention to adjusting them in accordance with 

regulations. The lower the return temperature that can be selected, the greater the expected 

solar yield. 

In this case it is important for all radiators to be adjusted in accordance with the applicable 

regulations (VOB part C: DIN 18380). A wrongly adjusted radiator can reduce the solar yield 

of the central heating considerably. 

The possibility of using the control unit must be checked with regard to the number of heating 

circuits. 

A so-called return temperature controller (RW) must be installed for all central heating backup 

systems. This monitors the central heating return temperature and prevents the solar cylinder 

from being heated up via the central heating return at high temperatures using a three-way 

distribution valve. The HZG kit can be used in combination with the FM443 solar function 

module or the SC40 solar control unit. 

Occasional heating 

If a wood burning fireplace insert or solid fuel boiler is only operated occasionally, the heat 

that is generated can be fed into the solar thermal store or combi cylinder. However, the solar 

yield is limited during this time. Simultaneous operation of the solar heating part of the system 

and solid fuel combustion must be minimised so that the solar yield is only reduced 

temporarily. This requires correct system engineering. 

Permanent heating 

If a wood burning fireplace insert or solid fuel boiler is to be used permanently in occasional 

alternating mode with an oil/gas fired boiler for central heating, a reduction in solar yield can 

be expected during the transition period due to the higher temperatures in the buffer part. 

Always comply with the current design/engineering document for solid fuel boilers. 

➔ page 52 f. 

➔ page 54 





➔ page 55 

➔ page 79 


➔ page 31 f. 

➔ page 55 



➔ page 70 ff.

Notes regarding solar heating systems 3 

3.2 Regulations and guidelines for designing/engineering a solar collector system 

➔ The guidelines shown here are only a selection and 

may not be complete. 

Installation and commissioning must be carried out by 

a specialist contractor. Take appropriate accident 

prevention measures when carrying out any 

installation work on the roof. Observe all relevant 

accident prevention regulations! 

Technical rules for the installation of solar heating systems 

Requirement Description 

Rooftop installation 

DIN 18338 VOB 1) ; roofing and sealing work 

DIN 18339 VOB 1) ; plumbing work 

DIN 18451 VOB 1) ; scaffolding work 

DIN 1055 Design loads for buildings 

Connection of solar heating systems 

Apply all current technical standards to all practical 

work. Design the safety equipment in accordance with 

all locally applicable regulations. Also comply with the 

building regulations of the country concerned, the 

listed building regulations and any local building 

regulations that may apply to the assembly and 

operation of a solar collector system. 

DIN EN 12975-1 Solar heating systems and components - Solar collectors - Part 1: 

General requirements, German version 

DIN EN 12976-1 Solar heating systems and components - Factory made systems - Part 1: 


DIN V ENV 12977-1 Solar heating systems and components - Custom built systems - Part 1: 


Installation and equipment of DHW cylinders 

DIN 1988 Technical Regulations for Drinking Water Installations (TRWI) 

DIN 4753-1 Water heaters and water heating installations for drinking water and service water; requirements, marking, 

equipment and testing 

DIN 18380 VOB1) ; heating systems and central DHW heating systems 

DIN 18381 VOB1) ; gas, water and sewage plumbing works inside of buildings 

DIN 18421 VOB 1) ; insulation work on technical installations 

AVB2) Water 

DVGW W 551 DHW heating and pipework systems; technical measures for reducing the growth of legionella bacteria 

Electrical connection 

DIN VDE 0100 Installation of HV systems with rated voltages up to 1000 V 

DIN VDE 0185 Lightning protection systems 

VDE 0190 Main earth bonding of electrical systems 

DIN VDE 0855 Antenna systems - to be applied analogous 

DIN 18382 VOB 1) ; electrical cabling systems in buildings 

59/1 Important standards, regulations and EC directives for the installation of solar collector systems 

1) VOB – contract procedures for construction work – part C: General technical conditions of contract for construction services (ATV) 

2) Invitation to tender templates for building work in overground workings, particularly with regard to residential building 


59

4 

Sample systems 

4 Sample systems 

4.1 Solar heating systems for domestic hot water heating with conventional 

oil/gas fired boilers 

4.1.1 Solar DHW heating floorstanding boiler and dual-mode cylinder 

Solar heating circuit 

The 1st consumer (dual-mode DHW cylinder) 

is heated subject to the temperature 

differential between FSK and FSS. 

60 


The boiler heats up the unmixed heating 

circuit. 


DHW reheating 

The DHW is reheated to the set temperature 

by the boiler subject to the FSX sensor, if 

required. Small system in accordance with 

DVGW Code of Practice W 551. 

60/1 Wiring diagram with short description of the sample system (General instructions ➔ page 57 f.; abbreviations ➔ page 148) 

Boiler Boiler Solar 

Floorstanding Control unit Type Control unit Component 

Logano with EMS 

Logano plus with EMS 

Logano 

FSK 

PSS 

SP1 

Logasol 

KS01.. 

I 

Collector 

Logamatic EMS RC35 SM10 

Logamatic 4000 4121 FM443 



Third party Third party Third party 

60/2 Possible control versions for the solar heating system 

FSX 

FSS 

PS 

HS-E - 

TW 

VS2 AW 

M1 

RS2 

VS1 

M2 

RS1 

WWM 

EZ 

EK 


HK1 

PH 

PZ 

Logamatic EMS 

+ SM10 

+ RC35 

SC20 

Boiler Logano 

Oil/Gas 

SC40 (hydraulic 

system T1 ➔ 37/1) 

FK 




Implement all safety equipment in 

accordance with local regulations. 

Logasol KS01.. I 


Logasol KS01.. SC.. I

4.1.2 Solar DHW heating: Wall mounted boiler and dual-mode cylinder 

FSK 







circuit. 


Sample systems 4 

DHW reheating 


by the boiler subject to the FSX sensor, if 





Wall Control unit Type Control unit Component 

Logamax with EMS 

Logamax plus with EMS 

Logamax 

Logamax plus 

PSS 

SP1 

Logasol 

KS01.. 

I 

Collector 

M1 

RS2 

VS1 

M2 

RS 1 




Logamatic 4000 4121 FM443 Logasol KS01.. I 



FSX 

FSS 

TW 

VS2 

AW 

WWM 

EZ 

EK 


HK1 

Logamatic EMS 

+ SM10 

+ RC35 






PZ 

GB142 

VK 

RK 

VS 

RS 

SC20 


system T1 ➔ 37/1) 

Logasol KS01.. SC.. I 

61

4 


4.1.3 Solar DHW heating: Floorstanding boiler and pre-heat cylinder (retrofit solution) 


The 1st consumer (pre-heat cylinder) is 

heated subject to the temperature differential 

between FSK and FSS. The water from both 

cylinders is transferred, if the standby 

cylinder is cooler than the pre-heat cylinder. 

62 

FSK 

SP1 



circuit. 


DHW reheating 


by the boiler subject to sensor FSX3, if 








Logano 

PSS 

Logasol 

KS01.. 

I 

Collector 

FSX1 

FSS 

TW 

RS 

VS 

M 

Logalux SU.../ST... 

Logamatic EMS RC35 

SM10 

SC10 


Logamatic 2000 2107 

FM244 

SC10 




1) Actuation via buffer water bypass circuit temperature differential 

AW 

SC40 

EK 

HS-E - 

HK1 

PH 

II 

P UM 

WWM 

PZ 


system T5 ➔ 37/1) 

Boiler 

Oil/Gas FK 

FSX3 

FSX2 

AW 

EZ 

EK 






Cylinder 

Logasol KS01.. 

P UM 


1) PUM Logasol KS01.. 

P UM 



P UM 

I 

II 

I 

II 

I 

II 

I 

II 

I 

II



4.1.4 Solar DHW heating: Wall mounted boiler and pre-heat cylinder (retrofit solution) 

FSK 

SP1 

PSS 




between FSK and FSS. The water from both 





circuit. 

DHW reheating 


by the boiler subject to sensor FSX3, if 








Logamax 

Logamax plus 

Logasol 

KS01.. 

I 

Collector 

FSX1 

FSS 

TW 

RS 

VS 

M 

HK1 

Logamatic EMS RC35 

SM10 

SC10 





1) Actuation via buffer water bypass circuit temperature differential 

AW 

SC40 

EK 


FSX3 

FSX2 

RS 

VS 

M2 

Boiler 

Gas 

II 

P UM 

AW 

EZ 

EK 

Cylinder 

WWM 

VK 

RK 

VS 

RS 

PZ 


system T5 ➔ 37/1) 







P UM 


1) 

PUM Logasol KS01.. 


P UM 

I 

II 

I 

II 

I 

II 

I 

II 

63

4 


4.2 Solar heating systems for DHW heating and central heating backup with 

conventional oil/gas fired boilers 

4.2.1 Solar DHW heating and central heating backup: Wall mounted boiler, dual-mode 

DHW cylinder and thermal store 




differential between FSK and FSS1. If the 1st 

consumer can no longer be heated, the 2nd 

consumer is heated subject to the 

temperature differential between FSK and 

FSS2. Possible heating of the 1st 

64 

consumer is checked at frequent intervals. 


The system return temperature is raised by 

the solar thermal store if there is a positive 

temperature differential between the FP and 

the FR. The temperature is increased to the 

required 


flow temperature by the wall mounted 

boiler. All heating circuits are equipped with 

a three-way valve. 

DHW reheating 


by the FSX sensor, if required. Small system in 

accordance with DVGW Code of Practice 

W551. 





Logamax plus with EMS 1) 

Logamax 

Logamax plus 

FSK 

SP1 

PSS 

II 

FP 

FSS 2 

I 

M1 

M4 

VS 1 

Collector 

Logasol 

KS01.. 

VS 2 

Logalux PL... 




RS3 

RS1 

SV 

HSM-E M 

III 


1) This system hydraulic scheme is not possible with the Logamax plus GB152 

FR 

A M B 

AB 

HK1 

PH 

FK 

1 

2 


+ FM443 

VK 

RK 

GB142 

KFE 

FSX 

FSS 1 

PS 

TW 

AW 

VS 2 

M1 

RS2 

VS1 

RS1 

M2 



system H5 ➔ 37/1) 

EZ 






WWM 

EK 

PZ 


VS-SU 

HZG kit 


VS-SU 

HZG kit 


VS-SU 

HZG kit 

I 

II 

III 

I 

II 

III 

I 

II 

III



4.2.2 Solar DHW heating and central heating backup: Wall mounted boiler, pre-heat 

cylinder and thermal store 

FSK 




between FSK and FSS1. The water from both 



If the 1st consumer can no longer be heated, 

the 2nd consumer is heated subject to the 


FSS2. Possible heating of the 1st consumer is 

checked at frequent intervals. 






required flow temperature by the wall 

mounted boiler. All heating circuits are 

equipped with a three-way valve. 

DHW reheating 




W 551. 






Logamax 

Logamax plus 

SP1 

PSS 

Logasol 

KS01.. 

I 

Collector 





TW 

FSS 

RS1 

VS1 

AB 

MB 2 

WWM 

MB1 

FSX 

EK 

PZ 

EZ VS3 

M4 

Logalux PL.../2S 

VS4 

FP 

RS4 

II 

PS 

A M B 

AB 

FR 

HSM-E 

HK1 

PH 

M 


system H5 ➔ 37/1) 


Oil/Gas 


VS-SU 

HZG kit 


VS-SU 

HZG kit 


VS-SU 

HZG kit 

This diagram is only a schem 

representation that provide 

guide to possible hydraulic 

Implement all safety equipm 

in accordance with local reg 

I 

II 

III 

IV 

I 

II 

III 

IV 

I 

II 

III 

SC10 P UM IV 

1 

2 Logamatic 

4 

+ FM443 

65

4 


4.2.3 Solar DHW heating and central heating backup: Floorstanding boiler and 

thermal store (retrofit solution) 




between FSK and FSS1. The water from both 



If the 1st consumer can no longer be heated, 

the 2nd consumer is heated subject to the 


66 

FSK 

SP1 

Log asol 

KS0 1..E 

II 

PSS2 

FP 

FSS2 

VS1 

RS1 








required 


flow temperature by the floorstanding boiler. 

All heating circuits are equipped with a threeway 

valve. 

DHW reheating 


by the FSX3 sensor, if required. Small system 

in accordance with DVGW Code of Practice 

W 551. 






Collector 

PSS1 

M1 

M4 

VS 2 

RS3 

Logasol 

KS01.. 

III 


Logano Logamatic 4000 4211 FM443 



I 

SC40 

Logalux PL... 

A M B 

AB 

FR 

HK1 

PH 

M 

FSS1 

FSX1 

HSM-E 

VS 

M 

RS 


TW 

AW 

EK 

SC10 

WWM 

IV 

P UM 


system H6 ➔ 37/1) 






PZ 

Boiler 

Oil/Gas 

FSX3 

FSX2 

AW 

EZ 

EK 


Logasol KS01.. E 

HZG kit 



HZG kit 



HZG kit 

Cylinder 

I 

II 

III 

IV 

I 

II 

III 

IV 

I 

II 

III 

SC10 P UM IV 

PS

4.2.4 Solar DHW heating and central heating backup: Floorstanding boiler, 

combi cylinder 

FSK 


The combi cylinder is heated subject to the 


FSS. The heating water and the DHW are 

heated. 



the combi cylinder if there is a positive 



required flow temperature by the 

floorstanding boiler. All heating circuits are 




DHW reheating 


by the floorstanding boiler subject to the FSX 

sensor, if required. Small system in 


W 551. 






Logano 

SP1 

PSS 

Logasol 

KS01.. 

I 

Collector 

TW 







FSS 

RS1 

VS1 

AB 

MB 2 

WWM 

MB1 

FSX 

EK 

PZ 

EZ VS3 

M4 


VS4 

FP 

RS4 

II 

PS 

A M B 

AB 

FR 

HSM-E 

HK1 

PH 

M 


system H1 ➔ 37/1) 


Oil/Gas 



guide to possible hydraulic schemes 


in accordance with local regulations 


HZG kit 


RW 


RW 


HZG kit 


HZG kit 

1 

2 Logamatic 

4121 

+ FM443 

I 

II 

I 

II 

I 

II 

I 

II 

I 

II 

67

4 


4.2.5 Solar DHW heating and central heating backup: Wall mounted boiler (GB142), 






heated. 

68 

FSK 

SP1 

PSS 

Logasol 

KS01.. 

I 

Collector 

TW 










DHW reheating 





W 551. 





Logamax plus with EMS1) Logamax 

Logamax plus 

FSS 

RS1 

VS1 





AW 

MB 2 

WWM 


1) This system hydraulic scheme is not possible with the Logamax plus GB152 

MB1 

FSX 

EK 

PZ 

EZ VS3 

VS4 

M4 FP 

RS4 

II 

A M B 

AB 

FR 

HSM-E 

HK1 

PH 

M 

FK 


+ FM443 

1 

2 


system H1 ➔ 37/1) 

VK 

RK 

VS 


HZG kit 


HZG kit 


HZG kit 



guide to possible hydraulic scheme 


in accordance with local regulation 

GB142 

I 

II 

I 

II 

I 

II



4.2.6 Solar DHW heating and central heating backup: Wall mounted boiler (GB152), 


FSK 

SP1 

PSS 

Collector 

Logasol 

KS01.. 

I 

TW 





heated. 









DHW reheating takes place via a third-party 

three-way valve GS-U (remove motor from 

internal three-way valve). 

DHW reheating 





W 551. 






Logamax 

Logamax plus 





FSS 

RS1 

VS1 

AW 

MB 2 

WWM 

MB1 

FSX 

EK 

PZ 

EZ VS3 


VS4 

M4 FP 

RS4 

II 

A M B 

AB 

FR 

HSM-E 

HK1 

PH 

M 

FK 


+ FM443 

1 

2 

VK 

RK 


system H1 ➔ 37/1) 

M 

MAG 

BC10 

U-KS11 

G-SU 


HZG kit 


HZG kit 


HZG kit 






GB152 

1) Remove motor from internal three-way changeover valve 

1) 

I 

II 

I 

II 

I 

II 

69

4 


4.3 Solar heating systems for DHW heating with solid fuel boiler 

4.3.1 Solar DHW heating: Floorstanding boiler, solid fuel boiler with dual-mode 






70 

FSK 


The floorstanding boiler or solid fuel boiler 

heats up the heating circuit. 


DHW reheating 




W 551. 




Logano with EMS 1) 

Logano plus with EMS 1) 

Logano 

SP1 

PSS 

FPO 

FPU 

Collector 

Logasol 

KS01.. 

I 

M1 

VS1 

VS2 

RS2 

RS3 

Logalux PR.../PS... 

HSM-E 

A M B 

AB 


1) Every boiler requires its own chimney 






FR 

HK1 

PH 

M 

FK 

PH 

Logamatic 

2114 


Logano S151 


Oil/Gas 

TW 

FSX 

FSS1 

FK 

PS 

TW 

AW 

VS2 

M1 

RS2 

VS1 

M2 

RS1 


SC20 

1 

2 

Logamatic 

4121 

+ FM443 

EZ 


system T1 ➔ 37/1) 

WWM 

EK 






PZ 



Logasol KS01.. I



4.3.2 Solar DHW heating: Wall mounted boiler, solid fuel-boiler with dual-mode 


FSK 

PSS 

SP1 

II 

FPO 

FP 

FSS2 

FPU 






The wall mounted boiler or solid fuel boiler 

heats up the heating circuit. 

DHW reheating 




W 551. 




Logamax with EMS 1) 


Logamax 

Logamax plus 

VS-SU 

Logasol 

KS01.. 

I 

M1 

M4 

VS 1 

Collector 

VS2 

VS3 

RS3 

RS2 

RS1 

Logalux PL... 

HSM-E 

III 

A M B 

AB 

FR 

HK1 






PH 

FK 

M 

PH 

FK 

Logamatic 

2114 

1 

2 


Logano S151 


+ FM443 

RK 

TW 

VK 

GB142 

FSX 

FSS1 

PS 

TW 

AW 

VS2 

M1 

RS2 

VS1 

M2 

RS1 

EZ 







SC20 

WWM 

EK 


system T1 ➔ 37/1) 

PZ 


71

4 


4.3.3 Solar DHW heating: Pellet boiler with dual-mode DHW cylinder and thermal store 





72 

FSK 


The solid fuel boiler heats up the thermal 

store to a constant temperature. 


DHW reheating 




W 551. 



Solid fuel Control unit Type Control unit Component 

Logano pellet Logamatic 4000 4211 P FM443 Logasol KS01.. I 

Logano solid fuel 

SP1 

PSS 

FK 

Logasol 

KS01.. 

Logamatic 4000 + 


Merchandise + 


S151 + 2114 + 4121 

SX11 + 4121 

Ixtronic + 4121 

S241 control unit + 

4121 



I 

M1 

Collector 

VS1 

VS2 

RS2 

RS3 

Logalux PR.../PS... 

HSM-E 

HK1 

PH 

M 

PH 

Logamatic 

4211P 

+ FM443 

Pellet boiler Logano SP... 

FM443 Logasol KS01.. I 

SC20 

FSX 

FSS1 

PS 


system T1 ➔ 37/1) 






TW 

AW 

VS2 

M1 

RS2 

VS 1 

M2 

RS1 

EZ 

WWM 

EK 


PZ 

Logasol KS01.. I



4.4 Solar heating systems for DHW heating and central heating backup with solid fuel 

boiler 

4.4.1 Solar DHW heating and central heating backup: Floorstanding boiler, solid fuel 

boiler with dual-mode DHW cylinder and thermal store 

FSK 

SP1 

Log asol 

KS0 1..E 

II 

PSS2 

Collector 

PSS1 






consumer (solar buffer) is heated subject to 

the temperature differential between FSK and 

FSS2. Possible heating of the 1st consumer 

is checked at frequent intervals. 






required flow temperature by the 

floorstanding boiler and the solid fuel 

boiler. The solar yield is reduced during solid 

fuel boiler operation. All heating circuits are 


DHW reheating 




W 551. 




Logano with EMS 1) 

Logano plus with EMS 1) 

Logasol 

KS01.. 



I 

SC40 




FPO 

FP 

FSS2 

FPU 

M1 

M4 

VS 1 

VS2 

VS3 

RS2 

RS3 

RS1 

Logalux PL... 

HSM-E 

III 

A M B 

AB 

FR 

HK1 

PH 

M 

FK 

PH 

Logamatic 

2114 

Logamatic 

2107 M 


Logano S151 


system H6 ➔ 37/1) 

FSX 

FSS1 

FK 

Floorstanding boiler 

Oil/Gas 

TW 

PS 

TW 

AW 

VS2 

M1 

RS2 

VS1 

M2 

RS1 

EZ 

WWM 

EK 




HZG kit 



HZG kit 



HZG kit 






I 

II 

III 

I 

II 

III 

I 

II 

III 

PZ 

73

4 


4.4.2 Solar DHW heating and central heating backup: Wall mounted boiler, solid fuel 

boiler with dual-mode DHW cylinder and thermal store 










74 







mounted boiler and the solid fuel boiler. The 

solar yield is reduced during solid fuel boiler 

operation. All heating circuits are equipped 

with a three-way valve. 


DHW reheating 




W 551. 




Logamax with EMS 1) 


Logamax 

Logamax plus 

FSK 

PSS 

SP1 

II 

FPO 

FP 

FSS2 

FPU 

VS-SU 

Logasol 

KS01.. 

Logalux PL... 



I 

M1 

M4 

VS 1 

Collector 




VS2 

VS3 

RS3 

RS2 

RS1 

HSM-E 

III 

A M B 

AB 

FR 

HK1 

PH 

FK 

M 

PH 

FK 

Logamatic 

2114 

1 

2 


Logano S151 


+ FM443 

RK 

TW 

VK 

GB142 

FSX 

FSS1 

PS 

TW 

AW 

VS2 

M1 

RS2 

VS1 

M2 

RS1 


system H5 ➔ 37/1) 

EZ 

WWM 

EK 








VS-SU 

HZG kit 


VS-SU 

HZG kit 


VS-SU 

HZG kit 

PZ 

I 

II 

III 

I 

II 

III 

I 

II 

III



4.4.3 Solar DHW heating and central heating backup: Solid fuel boiler with dual-mode 


FSK 

PSS 

SP1 















required flow temperature by the solid fuel 

boiler. All heating circuits are equipped with 

a three-way valve. 

DHW reheating 




W 551. 



Solid fuel Control unit Type Control unit Component 

Logano pellet Logamatic 4000 4211 P FM443 

Logano solid fuel 

II 

FPO 

FSS2 

FPU 

VS-SU 

Logasol 

KS01.. 

I 

M1 

M4 

VS 1 

Collector 

RS2 

RS3 

Logalux PL... 

Logamatic 4000 + 


Merchandise + 


S151 + 2114 + 4121 

SX11 + 4121 

Ixtronic + 4121 

S241 control unit + 

4121 



VS3 

VS2 

RS1 

HSM-E 

HK1 

PH 

M 

FK 

PH 

1 

2 

Logamatic 

4121 

+ FM443 

TW 

Solid fuel boiler Logano S241 






FSX 

FSS1 

FM443 

PS 

TW 

AW 

VS2 

M1 

RS2 

VS1 

M2 

RS1 


system H5 ➔ 37/1) 

EZ 

WWM 

EK 



VS-SU 


VS-SU 


VS-SU 

PZ 

I 

II 

I 

II 

I 

II 

75

4 


4.5 Solar heating systems for DHW heating and swimming pool heating with 

conventional oil/gas-fired boilers 

4.5.1 Solar DHW heating and swimming pool water heating: Floorstanding boiler 






consumer (swimming pool) is heated via the 

swimming pool heat exchanger SWT and the 

secondary circuit pump PS2 subject to the 


76 

FSK 

SP1 

PSS 

II 

between FSK and FSS2. Possible heating of 

the 1st consumer is checked at frequent 

intervals. 

DHW reheating 




W 551. 


Swimming pool water reheating 

The floorstanding boiler reheats the 

swimming pool water via a heating circuit 

with heat exchanger (WT). 

76/1 Wiring diagram with short description of the sample system (General instructions ➔ page 57f.; abbreviations ➔ page 148) 





Collector 

Logasol 

KS01.. 

I 

A M B 

AB 





FE 

FSS1 

AB 

VS 1 

RS 1 

WWM 

AW 

M 4 

FSX 

Logalux SL300-2, SL400-2, SL500-2 

M 

VS 

RS 

EK 

PS 

VK 

MAG 

RK 

1 

2 

FV3 


system S1 ➔ 37/1) 






M 

WT 

PH 

SH 


+ FM443 + FM442 

Boiler 

Logano EMS 

Oil/Gas 

PSB SMF 

III 

SWT 


VS-SU 

SWT 

PS2 


VS-SU 

SWT 

PS2 


VS-SU 

SWT 

PS2 

FSS2 

FSB 

PS2 

230 V 

50 Hz 

IV 

RSB 

I 

II 

III 

IV 

I 

II 

III 

IV 

I 

II 

III 

IV



4.5.2 Solar DHW heating and swimming pool water heating: Wall mounted boiler 

FSK 

SP1 

PSS 

II 






consumer (swimming pool) is heated via the 

swimming pool heat exchanger SWT and the 

secondary circuit pump PS2 subject to the 


between FSK and FSS2. Possible heating of 

the 1st consumer is checked at frequent 

intervals. 

DHW reheating 


subject to the FSX sensor, if required. Small 

system in accordance with DVGW Code of 

Practice W 551. 

Swimming pool water reheating 

The wall mounted boiler reheats the 

swimming pool water via a heating circuit 

with heat exchanger (WT). 

77/1 Wiring diagram with short description of the sample system (General instructions ➔ page 57f.; abbreviations ➔ page 148) 





Logamax 

Logamax plus 

Collector 

Logasol 

KS01.. 

I 

A M B 

AB 





FE 

FSS2 

AB 

FSS1 

VS 1 

RS 1 

WWM 

AW 

M 4 

Logamatic 

4121 

+ FM443 

FSX 

Logalux SL300-2, SL400-2, SL500-2 

M 

VS 

RS 

1 

2 

EK 






GB142 

SA 

VK 

SMF RK 

FV3 


system S1 ➔ 37/1) 

M 

WT 

PH 

SH 

PSB SMF 

III 

SWT 


VS-SU 

SWT 

PS2 


VS-SU 

SWT 

PS2 


VS-SU 

SWT 

PS2 

PS2 

230 V 

50 Hz 

FSS2 

FSB 

RSB 

IV 

I 

II 

III 

IV 

I 

II 

III 

IV 

I 

II 

III 

IV 

77

4 


4.6 Detailed hydraulic scheme for wall mounted boilers 

The individual device hydraulics are different for wall 

mounted boilers. For example, the three-way diverter 

valve in each boiler is installed into the boiler flow or 

return. 

Systems for solar DHW heating 

78 

The diagrams 78/1 and 78/2 show the hydraulic 

integration of several Buderus wall mounted boilers 

subject to the selected system hydraulic scheme. 

78/1 Detailed hydraulic scheme for wall mounted boilers in sample systems for solar DHW heating (abbreviations ➔ page 148) 

Systems for solar DHW heating and central heating backup 

VK 

RK 

VK 

RK 

SV 

Logamax plus 

GB152-16...24 

M SV 

ÜV 

AV 

VS RS 

MAG 

Logamax plus 

GB142 

MAG 

AV 

VS 

M 

PH 

Combi cylinder system 

Logamax plus 

GB142 

78/2 Detailed hydraulic scheme for wall mounted boilers in sample systems for solar DHW heating and central heating backup (abbreviations 

➔ page 148) 


VK 

RK 

VK 

RK 

SV 

MAG 

VS 

M 

AV 

PH 

RS 

Logamax plus 

GB142 

SV 

MAG 

M 

PH 

Two-cylinder system

5 Sizing 

5.1 Sizing principles 

5.1.1 Solar DHW heating 

Solar heating systems are most frequently used for 

DHW heating. Check each case individually as to 

whether it is possible to combined an existing heating 

system and a solar heating system. The conventional 

heat source must be able to provide the hot water in a 

building independently of the solar heating system. 

There is also an appropriate comfort requirement that 


Sizing 5 

must be reliably covered during periods of bad 

weather. 

Coverage of 50% to 60% is generally desirable for 

DHW heating systems for detached houses and twofamily 

homes. Sizing for less than 50% is also relevant 

if the available consumption values are unreliable. A 

coverage of less than 50% is generally appropriate in 

apartment blocks. 

5.1.2 Domestic hot water (DHW) heating and central heating backup 

Solar heating systems can also be designed as 

combination systems for DHW heating and central 

heating backup. Solar swimming pool water heating, 

combined with DHW heating and central heating 

backup is also possible. 

Since the system is operated at low temperatures 

during the spring and autumn, the type of heat 

distribution only plays a minor part in the efficiency of 

the system. A solar heating system for providing 

central heating backup can be realised in combination 

with an underfloor heating system and with radiators. 

5.1.3 Sizing with computer simulation 

It is advisable to size the solar heating system using 

computer simulation: 

● With six collectors or more, or 

● If there is a significant difference from the 

calculation conditions in the sizing diagrams 

(➔ 80/1 to 81/2 and 84/1 to 85/2) 

Correct sizing essentially depends on the accuracy of 

the information concerning the actual DHW demand. 

The following values are important: 

● Daily DHW demand 

● Daily profile, DHW demand 

● Weekly profile, DHW demand 

● Seasonal influence on the DHW demand (e. g. camp 

site) 

● Set DHW temperature 

● Existing DHW heating equipment (if an existing 

system is being extended) 

● Circulation losses 

The desired coverage for DHW heating systems 

combined with central heating backup is between 15% 

and 35% of the total annual heating demand for DHW 

and central heating. The achievable coverage is 

largely dependent on the building's heating demand. 

The Logasol SKS4.0 high-performance flat-plate 

collector and the Vaciosol CPC vacuum tube collector 

are particularly recommended as solar collectors for 

systems with central heating backup because of their 

high efficiency and dynamic response behaviour. 

● Location 

● Orientation 

● Slope 

The T-SOL simulation program is extremely practical 

for calculating solar heating systems. Simulation 

programs require consumption values as well as the 

size of the collector array and the cylinder. 

Consumption information should always be obtained, 

since values taken from literature are of little use. 

The collector array and the solar heating cylinder must 

therefore be pre-sized for the computer simulation 

(➔ page 80 ff.). The required output result is obtained 

in stages. 

The T-SOL program stores results such as temperatures, 

energy levels, efficiencies and coverage in a file. This 

information can be displayed on screen in many 

different ways and can be printed out for further 

analysis. 

79

5 

Sizing 

5.2 Sizing the collector array and solar heating cylinder 

5.2.1 Systems for DHW heating in detached houses and two-family homes 

Number of collectors 

Empirical values from detached houses and two-family 

homes can be used when a small solar heating system 

for DHW heating is being sized. The following factors 

influence the optimum sizing of the collector array, the 

cylinder and the compact station for solar collector 

systems for DHW heating: 

● Location 

● Roof slope (collector angle of inclination) 

● Roof orientation (south-facing collector) 

● DHW consumption profile 

Take the draw-off temperature in accordance with the 

existing or intended sanitary equipment into 

consideration. Basically, you orient yourself to the 

known number of occupants and the average 

consumption per person per day. Information about 

particular draw-off habits and comfort requirements 

are ideal. 

Calculation principles 

Diagrams 80/1 to 81/2 are based on a sample 

calculation with the following system parameters: 

● Logasol SKS4.0 high-performance flat-plate 

collectors, Logasol SKN3.0 flat-plate collectors and 

Vaciosol CPC6 vacuum tube collectors 

● Logasol SKS4.0: Logalux SL300-2 dual-mode 

thermosiphon cylinder (for more than three 

collectors: Logalux SL400-2) 

● Logasol SKN3.0: Logalux SM300 dual-mode cylinder 

(for more than three collectors: Logalux SM400) 

● Vaciosol CPC6: Logalux SL300-2 dual-mode 

thermosiphon cylinder (for more than three CPC6: 

Logalux SL400-2) 

● South-facing roof orientation (correction factor 

➔ page 82) 

● Roof incline 45° (correction factor ➔ page 82) 

● Location Würzburg 

● Draw-off temperature 45 °C 

➔ Determining the number of collectors or tubes in 

accordance with diagram 80/1, 81/1 or 81/2 results in 

a solar coverage of approx. 60%. 

80 

Example 

● Household with four occupants and a DHW demand 

of 200 l per day 

● Solar heating system for DHW heating 

➔ According to diagram 80/1, curve b, two Logasol 

SKS4.0 high-performance flat-plate collectors are 

required. 

Logasol SKS4.0 

80/1 Diagram for an approximate determination of the number of 

Logasol SKS4.0 collectors for DHW heating (example 

highlighted, observe calculation principles!) 


nSKS4.0 Number of collectors 

nP Number of occupants 

DHW demand curves: 

a Low (< 40 l per person per day) 

b Average (50 l per person per day) 

c High (75 l per person per day) 


n P 

8 

7 

6 

5 

4 

3 

2 

a 

c 

b 

1 1 2 3 4 5 

n SKS4.0 

6

Logasol SKN3.0 

n P 

8 

7 

6 

5 

4 

3 

2 


Logasol SKN3.0 collectors for DHW heating (observe 

calculation principles!) 


nSKN3.0 Number of collectors 

nP Number of occupants 

DHW demand curves: 

a Low (

5 

Sizing 

Influence of collector orientation and inclination on solar yield 

Optimum angle of inclination for collectors 

Use of solar heat for Optimum angle of 

inclination of 

collectors 

DHW 30°–45° 

Domestic hot water + central heating 45°–53° 

Domestic hot water + swimming pool 

water 

30°–45° 

Domestic hot water + central heating + 

swimming pool water 

45°–53° 

82/1 Angle of inclination of collectors subject to the use of solar 

heating system 

The optimum angle of inclination depends on the use 

of the solar heating system. The shallower optimum 

angles of inclination for DHW and swimming pool 

water heating take into account the higher position of 

the sun in the summer The wider optimum angles of 

inclination for central heating backup are designed for 

the lower sun position in spring and autumn. 

82 

Collector orientation according to the points of the 

compass 

Orientation in accordance with the points of the 

compass and the angles of inclination of the solar 

collectors have an influence on the thermal energy 

that is supplied by a collector array. Aligning the 

collector array south with a deviation of up to 10° east 

or west and an angle of inclination of 35° to 45° are the 

ideal conditions for maximum solar yield. 

If the collector array is mounted on a steep roof or a 

wall, the orientation of the collector array is identical 

to that of the roof or wall. If the collector array 

orientation deviates to the east or west, the rays of the 

sun will no longer strike the absorber area in the most 

effective way. This will reduce the performance of the 

collector array. 

According to table 82/2 there is a correction factor for 

every collector array deviation from the southern point 

of the compass, subject to the angle of inclination. The 

collector area that was determined under ideal 

conditions must be multiplied by this factor to achieve 

the same energy yield as is achieved with direct 

orientation south. 

Correction factors for solar collectors Logasol SKN3.0 and SKS4.0 for DHW heating 

Angle of 

Correction factors for collector orientation deviation from south 

inclination 

Deviation to the west by South Deviation to the east by 

90° 75° 60° 45° 30° 15° 0° –15° –30° –45° –60° –75° –90° 

60° 1.26 1.19 1.13 1.09 1.06 1.05 1.05 1.06 1.09 1.13 1.19 1.26 1.34 

55° 1.24 1.17 1.12 1.08 1.05 1.03 1.03 1.05 1.07 1.12 1.17 1.24 1.32 

50° 1.23 1.16 1.10 1.06 1.03 1.02 1.01 1.04 1.06 1.10 1.16 1.22 1.30 

45° 1.21 1.15 1.09 1.05 1.02 1.01 1.00 1.02 1.04 1.08 1.14 1.20 1.28 

40° 1.20 1.14 1.09 1.05 1.02 1.01 1.00 1.02 1.04 1.08 1.13 1.19 1.26 

35° 1.20 1.14 1.09 1.05 1.02 1.01 1.01 1.02 1.04 1.08 1.12 1.18 1.25 

30° 1.19 1.14 1.09 1.06 1.03 1.02 1.01 1.03 1.05 1.08 1.13 1.18 1.24 

25° 1.19 1.14 1.10 1.07 1.04 1.03 1.03 1.04 1.06 1.09 1.13 1.17 1.22 

82/2 Correction factors with south deviation of Logasol SKN3.0 and SKS4.0 solar collectors for different angles of inclination 

Correction ranges: 1.00–1.05 1.06–1.10 1.11–1.15 1.16–1.20 1.21–1.25 > 1.25 

➔ The correction factors only apply to DHW heating 

and not for central heating backup. 

Example 

● Parameters 

– Household with four occupants with DHW 

demand of 200 l per day 

– Angle of inclination 25° with rooftop installation 

or roof integration of Logasol SKS4.0 solar 

collectors 

– Deviation to the west by 60° 

● Measure 

– 1.8 Logasol SKS4.0 collectors (➔ Diagram 80/1) 

– Correction factor 1.10 (➔ Table 82/2) 

– The calculation results in: 1.8 × 1.10 = 2.0 

➔ To achieve the same energy yield as with direct 

southerly orientation, allow for 2 Logasol SKS4.0 solar 

collectors. 

Technical guide - Logasol solar technology for domestic hot water heating and central heating backup - 06/2007

Correction factors for Vaciosol vacuum tube collectors with DHW heating 

Cylinder selection 

A suitable ratio between collector output (size of 

collector array) and cylinder capacity (cylinder 

volume) is required to make a solar heating system 

operate efficiently. The size of the collector array is 

limited subject to the cylinder capacity (➔ 83/2). 

Always operate solar heating systems for DHW heating 

in a detached house with a dual-mode cylinder, if 

possible. A dual-mode solar cylinder has a solar heat 

exchanger and a heat exchanger for reheating by a 

boiler. In this concept the upper part of the cylinder 

acts as the standby part. Take this into consideration 

when selecting a cylinder. 

Two-cylinder systems are only worthwhile for greater 

DHW demands than can be covered by a dual-mode 

cylinder. In such systems, a mono-mode cylinder for 

accepting the solar heat is installed upstream of a 

conventional cylinder. The conventional cylinder must 


Sizing 5 

Angle of 

Correction factors for collector orientation deviation from south 

inclination 

Deviation to the west by South Deviation to the east by 

90° 75° 60° 45° 30° 15° 0° –15° –30° –45° –60° –75° –90° 

90° 2.4 2.0 1.9 1.8 1.8 1.9 2.0 1.9 1.8 1.8 1.9 2.0 2.4 

80° 2.0 1.7 1.6 1.5 1.5 1.5 1.6 1.5 1.5 1.5 1.6 1.7 2.0 

70° 1.7 1.5 1.4 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.4 1.5 1.7 

60° 1.6 1.4 1.3 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.3 1.4 1.6 

50° 1.4 1.3 1.2 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.2 1.3 1.4 

40° 1.3 1.2 1.1 1.1 1.0 1.0 1.0 1.0 1.0 1.1 1.1 1.2 1.3 

30° 1.3 1.2 1.1 1.1 1.0 1.0 1.0 1.0 1.0 1.1 1.1 1.2 1.3 

20° 1.2 1.1 1.1 1.1 1.0 1.0 1.0 1.0 1.0 1.1 1.1 1.1 1.2 

15° 1.2 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.2 

83/1 Correction factors with southerly deviation of Vaciosol vacuum tube collectors for different angles of inclination 

Correction ranges: 1.0–1.1 

1.2–1.3 1.4–1.6 1.7–2.4 

cover all DHW demands. The solar cylinder can 

therefore be somewhat smaller. 

This concept can also be used for retrofitting a solar 

heating system in a conventional system. However, the 

use of a dual-mode cylinder should always be 

considered for energy and financial reasons. 

Rule of thumb 

A cylinder volume of twice the daily demand has 

proven to be adequate. Table 83/2 shows standard 

values for selecting the DHW cylinder subject to the 

DHW demand per day for the relevant number of 

occupants. A cylinder temperature of 60 °C and a 

draw-off temperature 45 °C have been assumed. In a 

multi-cylinder system the stored volume of DHW 

should be able to cover twice the daily demand with a 

draw-off level of 85%. 

DHW 

Recommended 

Recommended number of occupants Capacity Rec. no. 

cylinder 

daily DHW demand in l 

1) 

Rec. no. of 

Logalux with cylinder temperature of 60 °C 

and draw-off temperature of 45 °C 

with a DHW demand per person per day of 

40 l 

50 l 

75 l 

Low Average High l 

Collectors 

SKN3.0 or 

SKS4.0 

CPC tubes 

SM300 up to 200/250 approx. 5–6 approx. 4-5 approx. 3 290 2–3 18 

SM400 up to 250/300 approx. 6-8 approx. 5-6 approx. 3-4 390 3–4 24 


SL300 up to 200/250 approx. 5-6 approx. 4-5 approx. 3 300 2–3 18 

SL400 up to 250/300 approx. 6-8 approx. 5-6 approx. 3-4 380 3–4 24 


SU160 2) 

SU200 2) 

up to 200/250 approx. 5-6 approx. 4-5 approx. 3 160 (300) 2–3 12 

up to 200/250 approx. 5-6 approx. 4-5 approx. 3 200 (300) 2–3 12 

83/2 Standard values for selecting the DHW cylinder 

1) Determining the number of collectors ➔ page 84 

2) Subject to the system configuration; relative to a total DHW volume of 300 l and water transfer between the pre-heating stage and the 

standby cylinder (sample system ➔ 45/1) 

83

5 

Sizing 

5.2.2 Systems for DHW heating and central heating backup in detached houses 

and two-family homes 


The sizing of the collector array for a solar heating 

system for DHW heating and central heating backup is 

directly dependent on the heating demand of the 

building and the required solar coverage. Only partial 

coverage is generally achieved during the heating 

season. 

➔ Diagrams 84/1 to 85/2 assume an average DHW 

demand for a 4-person household to be 50 l per person 

per day for DHW heating. 


Diagrams 84/1 to 85/2 are based on a sample 

calculation with the following system parameters: 

● Logasol SKS4.0 high-performance flat-plate 

collectors, Logasol SKN3.0 flat-plate collectors and 

Vaciosol CPC vacuum tube collectors 

● Logasol SKS4.0: 

Thermosiphon combi cylinder PL750/2S (for more 

than 8 collectors: Logalux PL1000/2S) 

● Logasol SKN3.0: 

P750 S combi cylinder (for more than six collectors: 

Logalux PL1000/2S) 

● Vaciosol CPC: 

Thermosiphon combi cylinder PL750/2S (for more 

than 42 CPC tubes: Logalux PL1000/2S) 

● Household with four occupants with a DHW 


● Roof orientation towards south 

● Roof pitch 45° 


● Low temperature heating with ϑ V =40°C, ϑ R = 30 °C 

Example 

● Household with four occupants with a DHW 


● Solar heating system for DHW heating and 

underfloor heating backup 

● Heating demand 8 kW 

● Required coverage 25% 

➔ According to diagram 84/1, curve c, six Logasol 

SKS4.0 high-performance flat-plate collectors are 

required. 

84 



Logasol SKS4.0 collectors for DHW heating and central heating 

backup (example highlighted, observe calculation principles!) 


nSKS4.0 Number of collectors 

QH Building heating demand 

Curves for coverage of total annual heating demand for DHW 

heating and central heating 

a Coverage of approx. 15 % 

b Coverage of approx. 20 % 

c Coverage of approx. 25 % 

d Coverage of approx. 30 % 

e Coverage of approx. 35 % 


Q H 

kW 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 1 2 3 4 5 

n SKS4.0 

a 

b 

c 

d 

e 

6 7 8 9 10


Q H 

kW 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 1 2 3 4 5 


Logasol SKN3.0 collectors for DHW heating and central 

heating backup (observe calculation principles!) 


nSKN3.0 Number of collectors 









a 

n SKN3.0 

b 

c 

d 

e 

6 7 8 9 10 

Vaciosol CPC 


nCPC Number of tubes 










QH kW 

18 

16 

14 

12 

10 

8 

6 

4 

2 

Sizing 5 

0 

6 12 18 24 30 

nCPC 36 42 48 54 60 


Vaciosol CPC tubes for DHW heating and central heating 

backup (observe calculation principles!) 

a 

b 

c 

d 

e 

85

5 

Sizing 

Cylinder selection 

Solar heating systems for DHW heating and central 

heating backup should be operated using a 

combination cylinder if possible. When a cylinder is 

being selected ensure that the DHW standby part 

corresponds to the user's usage pattern. 

As well as providing an adequate supply of DHW, a 

solar heating system for DHW heating and central 

heating backup must also take the building heating 

demand into consideration. 

DHW cylinder Recommended 


86/1 Standard values for selecting the combi cylinder 


Alternatively it is possible to install a two-cylinder 

system instead of a combi cylinder. This would be 

particularly advisable if an additional DHW demand 

or buffer water demand arises due to an additional 

86 

Recommended 

number of 

occupants 

Table 83/2 shows standard values for selecting the 

combi cylinder subject to the DHW demand per day for 

the relevant number of occupants, and the 

recommended number of collectors. A cylinder volume 

of at least 100 l must be available per flat-plate 

collector to minimise stagnation times. 

The total coverage can be sized in accordance with 

diagrams 84/1 to 85/2. A detailed result is provided by 

simulation using a suitable simulation program. 

Capacity 

DHW/total 

Logalux at a cylinder temperature of 60 °C 

and draw-off temperature of 45 °C l 

Recommended 

number 1) 

of collectors 

SKN3.0 or SKS4.0 

consumer. The number of collectors must be adapted 

to the demand of the additional consumer in this case 

(e.g. swimming pool or thermal store). 


Recommended 

number 

of CPC tubes 

P750 S up to 200/250 approx. 3-5 160/750 4–6 36–48 

PL750/2S up to 250/350 approx. 3-9 300/750 4–8 36–48 

PL1000/2S up to 250/350 approx. 3-9 300/940 6–10 48–60 

Duo FWS750 up to 200/250 approx. 3-5 38/750 4–6 36–48 

Duo FWS1000 up to 250/350 approx. 3-6 38/1000 4–8 48–60 

DHW cylinder Recommended 


Logalux 

at a cylinder temperature of 60 °C 

and draw-off temperature of 45 °C 

86/2 Standard values for selecting the DHW cylinder for a two-cylinder system. 


Recommended number of occupants Cylinder 

with DHW demand per person per day of 

capacity 

40 l 

Low 

50 l 

Average 

75 l 

High l 

Rec. 

number 1) 

of collectors 

SKN3.0 

or 

SKS4.0 

Rec. 

number of 

CPC tubes 

SM300 up to 200/250 approx. 5-6 approx. 4-5 approx. 3 290 2–3 18 



SL300 up to 200/250 approx. 5-6 approx. 4-5 approx. 3 300 2–3 18 



DHW cylinder Buffer capacity Recommended number of 1) SKN3.0 or 

SKS4.0 collectors 

Logalux l 

86/3 Standard values for selecting the thermal store for a two-cylinder system. 


Recommended number of CPC tubes 

PL750 750 4–8 36–48 

PL1000 1000 4–8 48–60 

PL1500 1500 6–16 72–108

5.2.3 Apartment blocks with 3 to 5 residential units 

Dual-mode cylinder in large systems 

With large systems as defined by the DVGW 

[Germany], the water delivered by the DHW heating 

system must always be at a temperature of ≥ 60 °C. 

The entire contents of pre-heating stages must be 

heated to ≥ 60 °C at least once per day. 

For small detached houses the pre-heating stage (the 

part of the cylinder volume that is heated by the solar 

heating system) and the standby part (conventionally 

heated cylinder volume) must also be combined in a 

dual-mode cylinder. The daily heating is made 

possible by a water transfer between the standby part 

and the pre-heating stage. A connecting line with 

circulation pump is provided for this purpose between 

the DHW outlet and the cold water inlet of the dual- 

FSK 

SP1 

PSS 

Logasol 

KS01.. 

Collector 

PS 

FSX 

FSS 

M1 

RS 2 

VS 1 

M2 

RS 1 

VS 2 AW 

TW 

EZ 

EK 


HK1 

HS-E PH 

PUM 

WWM 


Sizing 5 

mode cylinder. The pump is actuated via the FM443 

solar function module. 

This means that a coverage of approx. 30% can be 

achieved for a system with a Logalux SM500 or SL500 

cylinder with 4 or 5 collectors and a DHW demand of 

100 l at 60 °C per residential unit. 

➔ When sizing the cylinder ensure that the DHW 

demand can also be covered without solar yield via 

conventional reheating. 

Daily heating/pasteurisation control 

Pasteurisation control can only be used and completed 

successfully if the same conditions as those for 

apartment blocks with up to 30 residential units are 

met (➔ page 89). 

87/1 Example of hydraulic integration of a dual-mode cylinder in large systems for apartment blocks of 3 to 5 residential units; control of cylinder 

water transfer and pasteurisation control in accordance with DVGW Code of Practice W 551 using solar function module FM443 

(abbreviations ➔ page 148) 

PZ 

FK 


Oil/Gas 






1 

2 


+ FM443 

87

5 

Sizing 

5.2.4 Apartment blocks with up to 30 residential units 

Two-cylinder system with pre-heating stage 

The daily heating of the pre-heating stages must 

always be taken into consideration when solar heating 

systems are being planned in combination with large 

systems for DHW heating in accordance with the 

DVGW. This ensures that hygiene is maintained, and 

simultaneously raises the average temperature level in 

the solar pre-heating stage. 

In smaller large systems with a uniform consumption 

profile (e.g. an apartment block) or lesser coverage 

requirements of approx. 20% to 30%, systems with preheating 

stages filled with DHW are frequently a 

financially interesting solution in spite of the required 

daily heating. However, the daily heating reduces the 

yield considerably in systems with greater coverage 

requirements of approx. 40% and the associated large 

solar buffer volumes. A switch to thermal stores filled 

with heating water with additional heat transfer to the 

DHW is a frequent response for such systems. These 

also offer the advantage that integrating the solar 

heating system only leads to a slight increase in DHW 

volume with the SAT-VWS system and none at all with 

88 

FSK 

PSS 

SP1 

Logasol 

KS01.. 

Collector 

FSS 

TW 

RS 

VS 

M 

AW 

EK 


HS-E - 

HK1 

PH 

FSX 

PS 

the SAT-ZWE system. Separate engineering documents 

are available for these systems. 

Systems with DHW cylinders are suitable for 

retrofitting, since the pre-heating stage and the 

standby part have separate cylinders. The pre-heating 

stage and the standby cylinder can be sized separately. 

The set temperature for the standby cylinder is at least 

60 °C. Solar heating must be enabled up to 75 °C so 

that the solar heating system can utilise the entire 

cylinder volume. The solar function module FM443 or 

solar control unit SC40 switches pump PUM ON for a 

water transfer between the two cylinders if the preheating 

cylinder is hotter than the standby cylinder. 

This means that both cylinders are heated above the 

set temperature, and the heat loss due to DHW 

circulation can also be covered by solar energy. 

The water transfer is started at a preset time during the 

night if the required pasteurisation temperature of 

60 °C is not achieved during the day. 

88/1 Diagram of a two-cylinder system as large system with pre-heat cylinder and standby cylinder filled with DHW; cylinder water transfer and 

pasteurisation control regulated in accordance with DVGW Code of Practice W 551 by solar function module FM443 (abbreviations 

➔ page 148) 


RS 

VS 

M 

PUM 

AW 

EZ 

WWM 

EK 





Implement all safety equipment in 

accordance with local regulations. 

PZ 

FK 


Oil/Gas 

1 

2 


+ FM443

Daily heating/pasteurisation control 

The following conditions must be complied with to 

enable pasteurisation control to be used and 

completed successfully: 

● Pasteurisation of the pre-heat stage must take place 

during periods where no DHW is drawn. This 

requirement is easiest to comply with at night. 

● The flow rate for pasteurisation should be selected so 

that the content of the pre-heat cylinder is circulated 

at least twice per hour. It is advisable to use a threestage 

pump that delivers appropriate reserves. 

● The temperature of the standby cylinder must not drop 

below the 60 °C limit whilst pasteurisation is taking 

place. The output for pasteurisation must not be 

greater than the maximum output for conventional 

reheating of the standby cylinder so that the 

temperature in the standby cylinder does not drop. 

● To minimise the heat loss between the standby 

cylinder and the pre-heat cylinder, the line must be 

adequately insulated to a high thermal insulation 

standard. 

Collector area sizing 

Apply a daily consumption of approx. 70 l to 75 l of 

DHW at 60 °C per m² of collector area for sizing the 

collector area in properties with a uniform 

consumption profile, such as in apartment blocks. 

Estimate the DHW demand with care, since less 

utilisation would lead to a considerable increase in the 

stagnation time of this system. Higher utilisation helps 

to improve the system resilience. 

By way of simplification, the following formulae can 

be used taking the specified marginal conditions into 

consideration: 


Sizing 5 

● Keep the pasteurisation line as short as possible (close 

proximity to pre-heat or standby cylinder). 

● The DHW circulation must be switched off during preheat 

stage pasteurisation (no cooling by circulation 

return into the standby cylinder). 

● If the control unit for heating the standby cylinder has 

a function for temporarily increasing the set 

temperature in the cylinder, the time window of this 

function must precede (e.g. 1/2 h) the time window for 

pre-heat cylinder pasteurisation (synchronise both 

time windows). 

● Check the pasteurisation function during the system 

commissioning. Select conditions that are identical to 

the subsequent operating conditions. 

n SKS4.0 =0.6·n WE 

n SKN3.0 =0.7·n WE 

n CPC12 =0.5·n WE 

89/1 Formulae for the required number of Logasol SKS4.0, SKN3.0 

and Vaciosol CPC12 solar collectors in relation to the number 

of residential units (observe marginal conditions!) 

Calculating sizes 

nSKS4.0 Number of Logasol SKS4.0 solar collectors 

nSKN3.0 Number of Logasol SKN3.0 solar collectors 

nCPC12 Number of Vaciosol solar collectors with 12 tubes 

nWE Number of residential units 

Marginal conditions for formulae ➔ 89/1 

● Pasteurisation control at 02:00 h 

● New building circulation cost: 100 W/apartment 

Old building: 140 W/RU 


● Pre-heat cylinder temperature max. 75 °C, water 

transfer enabled 

● 100 l/RU at 60 °C 

89

5 

Sizing 

Cylinder volume sizing 

The DHW cylinders connected in series must be 

equipped with a water transfer facility. Ensure that 

daily heating takes place, and also a transfer of hotter 

water from the pre-heat cylinder to the standby 

cylinder. The cylinder volume for the solar heating 

system then consists of the volume of the pre-heat 

cylinder plus the volume of the standby cylinder. 

Observe the sensor positions that are required during 

cylinder selection. A cylinder with removable flexible 

foam insulation makes it possible to attach additional 

contact sensors, e.g. using straps. 


The minimum pre-heat cylinder volume should be 

approx. 20 l per square metre of collector area: 

90/1 Formula for minimum pre-heat cylinder volume in relation to 

the collector area 


AK Collector area in m2 VVWS,min Minimum pre-heat cylinder volume in l 

An increase in the specific cylinder volume increases 

the system resilience regarding consumption 

fluctuations, on the other hand more conventional 

energy would be required for daily heating. 

The pre-heat cylinder must provide a facility for 

positioning two additional sensors at 20 % and 80 % of 

the cylinder height. 

The maximum number of collectors for the Logalux SU 

pre-heat cylinder as per table 90/2 applies to a 

maximum cylinder temperature of 75 °C and solar 

heating system coverage of 25% to 30%. A heat 

transfer to the collector circuit is not safeguarded if the 

maximum cylinder temperature is exceeded. 

Simulations must be used to verify that stagnation is 

unlikely to occur. This is particularly important for 

properties with limited summer use (e.g. schools). 

90 

V VWS ,min = A K ·20l/m 2 

pre-heat cylinder Number of solar collectors 

Logalux SKN3.0 SKS4.0 CPC12 

SU400 16 14 11 

SU500 20 16 13 

SU750 22 18 15 

SU1000 25 21 17 

90/2 Maximum number of collectors for a Logalux SU pre-heat 

cylinder (with a maximum cylinder temperature of 75 °C and 

solar heating system coverage of 25% to 30%) 

Standby cylinder 

The standby cylinder is not heated at a lower 

temperature differential (maximum temperature 

minus reheat temperature) than the pre-heat cylinder, 

but this cylinder provides about one third of the 

necessary cylinder capacity because of its larger 

volume. The heating of the standby cylinder also 

enables an integration and provision of solar coverage 

of the heat loss resulting from the DHW circulation. 

The standby cylinder is sized in accordance with 

conventional heat demand without taking the preheat 

cylinder volume that is heated using solar energy 

into consideration. However, the specific total cylinder 

volume should be approx. 50 l per square metre of 

collector area: 

VBS + VVWS AK ------------------------ 50 l/m 2 

≥ 

90/3 Formula for minimum total cylinder volume of pre-heat stage 

and standby part per square metre of collector area 


AK Collector area in m2 VBS Standby cylinder volume in l 

VVWS Pre-heat cylinder volume in l 


5.2.5 Swimming pool water heating systems 

The weather conditions and the swimming pool heat 

loss into the ground have a considerable influence on 

sizing. For that reason, sizing a solar heating system 

for heating swimming pool water can only ever be 

approximate. Basically, the sizing has to be oriented to 

the area of the pool. The water cannot be guaranteed 

to be at a certain temperature over several months. 

Standard values for indoor swimming pools with covers. 

Conditions for standard indoor swimming pool values 

● Pool basin covered when not in used (insulation) 

● Set pool water temperature 24 °C 

Example 


– Indoor swimming pool, covered 

– Pool surface 32 m2 – Pool water temperature 25 °C 

● Wanted 

– Number of Logasol SKS4.0 solar collectors for solar 

swimming pool water heating 

Standard values for outdoor swimming pools 

The standard values only apply if the swimming pool 

is insulated and embedded in the ground in a dry 

condition. First insulate the pool if the swimming pool 

is at the level of groundwater without insulation. Then 

carry out a heat demand calculation. 

Covered outdoor swimming pool (or indoor 

swimming pool without insulation) 

A ratio of 1:2 applies as standard value. This means 

that the area of a collector array with Logasol SKN or 

SKS must be half the size of the pool surface area. The 

standard value is 1:3 for vacuum tube collectors. 


Sizing 5 

➔ If the solar swimming pool water heating system is 

combined with DHW heating, we recommend the use 

of a Logalux SM... dual-mode solar heating cylinder 

with a large solar indirect coil and limited cylinder 

heating up to 60 °C. 

If the required set water temperature is higher than 

24 °C, the number of required collectors increases by 

the correction factor in table 91/1. 

Range Reference size Sizing with solar collectors 

SKN3.0 SKS4.0 CPC 

Pool surface Pool surface in m 2 1 collector for every 5 m 2 1 collector 

for every 6.4 m 2 

Correction factor for pool 

water temperature 

Deviation above 24 °C pool 

water temperature 

1.3 additional collectors 1 additional collector 

For every +1 °C above a pool water temp. of 24 °C 

12 tubes for every 8 m 2 

1 additional 

CPC12 collector 

91/1 Standard values for calculating the number of collectors for swimming pool water heating for a covered indoor swimming pool (insulation). 

● Read off (➔ 91/1) 

– 5 Logasol SKS4.0 solar collectors for pool area of 

32 m 2 

– 1 Logasol SKS4.0 solar collector as correction for 

+1 °C above 24 °C pool water temperature 

➔ Six Logasol SKS4.0 solar collectors are required for 

solar swimming pool water heating. 

Outdoor swimming pool without insulation 

In this case the standard value ratio is 1:1. This means 

that the area of a collector array comprising Logasol 

SKN or SKS must be the same size as the pool surface. 

The standard value is 1:2 for vacuum tube collectors. 

If the solar heating system is intended for an outdoor 

swimming pool, DHW heating and/or central heating 

backup, add the required collector areas for the 

swimming pool water and DHW. Do not add the 

collector areas for central heating. The solar heating 

system heats the outdoor swimming pool in summer 

and central heating in winter. DHW is heated all year 

round. 

91

5 

Sizing 

5.3 Space requirements for solar collectors 

5.3.1 Space requirement with rooftop installation and roof integration 

Logasol solar collectors can be installed on steep roofs 

with a pitch of 25° to 65° and offer two installation 

options. These are rooftop installation (➔ page 123 ff.) 

and roof integration (➔ page 130 ff.). Installation on 

corrugated sheets and sheet metal roofs (rooftop 

installation only) can only be carried out on roof 

pitches between 5° and 65°. 

The minimum angle of inclination for vacuum tube 

collectors with rooftop installations is 15°. Roof 

integration is not possible. 

➔ At the planning stage, the amount of space required 

beneath the roof must be taken into consideration as 

well as the area required on top of the roof. 

Dimensions A and B represent the area requirement 

for the selected number and layout of collectors (➔ 93/1 

to 93/3). With roof integration they include the area 

required for the collectors and their connection kits. 

These dimensions must be considered to be the 

minimum requirements. Installation with two persons 

is made easier by also removing one or two rows of tiles 

around the collector array. For this, dimension C is 

regarded as the upper limit. 

Dimension C represents at least two rows of tiles (three 

rows of tiles with the Vaciosol CPC) up to the roof ridge. 

If the tiles are laid in concrete there is a risk of 

damaging the roof cover at the roof ridge. 

Dimension D represents the roof overhang, including 

the gable end thickness. The adjacent 0.5 m (0.3 m 

with the Vaciosol CPC) space from the collector array 

is required beneath the roof, subject to the connection 

version (right or left). 

Allow 0.5 m to the right and/or left of the collector 

array for the connection lines (beneath the roof!). 

92 

Allow 0.3 m beneath the collector array (beneath the 

roof!) for routing the return connection line. 

➔ Route the return line with a rise to the automatic air 

vent valve if the system is not filled using a filling 

station. 

Allow 0.4 m above the collector array (beneath the 

roof!) for routing the flow header (rising) and the air 

cowl with automatic air vent valve if the system is not 

filled using a filling station. 

≥ 0.5 

92/1 Space requirements for rooftop and roof integration of solar 

collectors (explanation in the text body); dimensions in m 


C 

A 

≥ 0.5 

D 

B 

≥ 0.3 

D 

≥ 0.4

Area required for solar collector rooftop and roof integration installation 

C 

B 1 2 3 4 5 6 7 8 9 10 

Y 

B 

1 2 3 4 5 6 7 8 9 10 

A 

93/1 Area required for collector arrays for rooftop and roof integration installation (dimensions ➔ 93/2 and 93/3) 

Dimensions Collector array dimensions for Logasol flat-plate collectors 

SKN3.0 and SKS4.0 SKN3.0 and SKS4.0 

at 

rooftop installation 

at 

roof integration 

portrait landscape portrait landscape 

A for 1 collector m 1.15 2.07 – – 

for 2 collectors m 2.32 4.17 2.67 4.52 









B m 2.07 1.15 2.80 1.87 

C 2 rows of tiles 2 rows of tiles 2 rows of tiles 2 rows of tiles 

X ≈0.20 m ≈0.20 m 3 rows of tiles 3 rows of tiles 

Y subject to roof 

subject to roof 

– – 

construction 

construction 

(batten spacing) (batten spacing) 

93/2 Collector array dimensions with Logasol flat-plate collectors for rooftop and roof integration installation (➔ 92/1 and 93/1) 

Dimensions Collector array dimensions for Vaciosol vacuum tube collectors 

CPC6 CPC12 

for 


for 


one row two rows one row two rows 

A for 6 tubes m 0.70 0.70 – – 

for 12 tubes m 1.40 1.40 1.40 1.40 

for 18 tubes m 2.15 2.15 – – 

for 24 tubes m 2.85 2.85 2.80 2.80 

for 30 tubes m 3.55 3.55 – – 

for 36 tubes m 4.25 4.25 4.20 4.20 

B m 2.10 4.15 2.10 4.15 

93/3 Collector array dimensions with Vaciosol vacuum tube collectors for rooftop installation (➔ 92/1 and 93/1) 

X 

A Width of collector row 

B Height of collector row 

C Distance from roof ridge (at least two rows of tiles ➔ 92/1) 

X Distance between collectors rows side by side 

Y Distance between collectors rows above each other 


Sizing 5 

93

5 

Sizing 

5.3.2 Space required for flat roof installation 

Flat roof installation is possible with portrait and 

landscape Logasol SKS4.0 or SKN3.0 collectors and 

with Vaciosol CPC vacuum tube collectors. The area 

required for the collectors corresponds to the 

installation area for the flat roof supports used plus a 

space for pipework routing. This space should be at 

least 0.5m to the left and right of the array. Maintain 

a minimum distance of one metre from the roof edge. 

94/1 Flat roof stand installation dimensions on the example of 

Logasol SKN3.0-s and SKS4.0-s portrait flat-plate collectors 

(dimension A ➔ 94/2 and dimension B ➔ 94/3) 

94 

A 

Number of Collector row dimensions for Logasol 

collectors 

SKN3.0 and SKS4.0 

portrait landscape 

A A 

m m 

2 2.34 4.18 

3 3.51 6.28 

4 4.68 8.38 

5 5.85 10.48 

6 7.02 12.58 

7 8.19 14.68 

8 9.36 16.78 

9 10.53 18.88 

10 11.70 20.98 

94/2 Collector row dimensions when using flat roof supports 

Angle of Collector row dimensions for Logasol 

inclination 


portrait landscape 

B B 

m m 

25° 1.84 1.06 

30° 1.75 1.02 

35° 1.68 0.96 

40° 1.58 0.91 

45° 1.48 0.85 

50° 1.48 0.85 

55° 1.48 0.85 

60° 1.48 0.85 


B 

A B 

94/4 Flat roof stand installation dimensions for Vaciosol CPC6 and 

CPC12 vacuum tube collectors (dimension A ➔ 94/5 and 

dimension B ➔ 94/6) 

Number of Collector row dimensions for Vaciosol 

tubes 

CPC6 CPC12 

one row one row 

A A 

m m 

6 0.70 – 

12 1.40 1.40 

18 2.15 – 

24 2.85 2.80 

30 3.55 – 

36 4.25 4.20 



tubes 

CPC6 CPC12 

one row one row one row one row 

with 30° with 45° with 30° with 45° 

B B B B 

m m m m 

6 1.82 1.49 – – 

12 1.82 1.49 1.82 1.49 

18 1.82 1.49 – – 

24 1.82 1.49 1.82 1.49 

30 1.82 1.49 – – 

36 1.82 1.49 1.82 1.49 



Minimum row spacing 

If several rows of collectors are installed behind each 

other, they must be a minimum distance apart to 

minimise the shading on the collectors at the back. 

Standard values that apply to standard sizing apply to 

this minimum spacing (➔ 95/3). 

sinγ 

X = L ⋅ ⎛----------- + cosγ⎞ 

⎝tanε ⎠ 

95/1 Formula for minimum row spacing for flat roof installation 

L 

95/2 Calculation parameter display (formula ➔ 95/1) 

X 

Calculation parameters (➔ 95/1 and 95/2) 

X Free minimum spacing between collector rows (standard values 

➔ 95/3) 

L Length of solar collectors 

γ Collector angle of inclination relative to the horizontal (standard 

values ➔ 95/3) 

ε Minimum solar altitude relative to the horizontal without shading 

Angle of 

inclination 1) 


Sizing 5 

Free minimum space X between collector rows 

for Logasol 


for Vaciosol 

CPC6 and CPC12 

portrait landscape portrait 

γ m m m 

25° 2) 

30° 3) 

4.74 2.63 – 

5.18 2.87 34) 35° 5.58 3.09 – 

40° 5.94 3.29 – 

45° 6.26 3.46 3.55) 50° 6.52 3.61 – 

55° 6.74 3.73 – 

60° 6.90 3.82 – 

95/3 The standard values for the minimum space between collector 

rows at different angles of inclination (➔ 95/2; relative to the 

minimum solar altitude without shading of 17° as the mean 

between the Münster and Freiburg locations on the 21st 

December at 12.00 h (midday)) 

1) Only these angles of inclination are approved by the 

manufacturer. The use of different positions could damage 

the system. 

2) Adjustable by trimming the telescopic strut 

3) Adjustable by trimming the telescopic strut with landscape 

collectors 

4) Angle of inclination only meaningful for DHW heating 

5) Angle of inclination only meaningful for combined DHW 

and central heating backup 

95

5 

Sizing 

5.3.3 Space requirements for wall mounting 

Logasol flat-plate collectors 

Wall mounting is only suitable for Logasol SKN3.0-w 

and SKS4.0-w landscape flat-plate collectors, and is 

only approved for an installation height of up to 20 m. 

The wall must have adequate load-bearing capacity 

(➔ page 138)! 

The space requirement on the wall for the collector rows 

depends on the number of collectors. In addition to the 

width of the collector array, allow at least 0.5 m to the left 

and right (dimension A ➔ 96/2) for routing the 

pipework. The space between the collector row and the 

edge of the wall must be at least one metre. 

96/1 Installation dimensions of wall mounting kits for Logasol 

SKN3.0-w and SKS4.0-w landscape flat-plate collectors; 

dimensions in m (dimension A ➔ 96/2) 

96 

A 

Number of Collector row dimensions for Logasol 

collectors 

SKN3.0-w and SKS4.0-w 

landscape 

A 

m 

2 4.17 

3 6.26 

4 8.36 

5 10.45 

6 12.55 

7 14.64 

8 16.74 

9 18.83 

10 20.93 

96/2 Collector row dimensions when using wall mounting supports 

0.85 

Minimum row spacing 

The wall mounting kit is particularly suitable for 

buildings the roof orientation of which deviates 

considerably from south or for providing windows and 

doors with shade. From a technical point of view this 

allows the best possible use to be made of the sun, and 

also represents an architectural feature. 

In summer the collector provides ideal shade for 

windows and keeps the rooms nice and cool. In winter, 

when the sun is at a low altitude, the rays if the sun can 

shine into the window below the collector and 

therefore provide an additional source of energy. 

➔ Several rows of collectors arranged above of each 

other must be kept at least 3.7 m apart to prevent the 

collectors from casting shadows on each other 

(➔ 96/3). This space can be reduced if "freedom from 

shade" is not required. 

96/3 Shade-free spacing for several rows of wall installation kits for 

landscape flat-plate collectors arranged above each other. 

Logasol SKN3.0-w and SKS4.0-w; dimension in m 


3,7

Vaciosol vacuum tube collectors 

Vaciosol CPC vacuum tube collectors can be fitted to 

the wall with an angle of inclination of 45° or 60° using 

flat roof support. 

Portrait installation is possible using a rooftop 

installation kit. The wall must have an adequate loadbearing 

capacity. The header must generally be 

installed at the top. 

97/1 Installation dimensions of wall installation kits with angled 

frames for Vaciosol CPC6 and CPC12 vacuum tube collectors. 

(dimension A ➔ 97/2 and dimension B ➔ 97/3) 


tubes 

CPC6 CPC12 

one row one row 

A A 

m m 

6 0.70 – 

12 1.40 1.40 

18 2.15 – 

24 2.85 2.80 

30 3.55 – 

36 4.25 4.20 



tubes 

CPC6 CPC12 

one row one row one row one row 

with 30° with 45° with 30° with 45° 

B B B B 

m m m m 

6 1.82 1.52 – – 

12 1.82 1.52 1.82 1.52 

18 1.82 1.52 – – 

24 1.82 1.52 1.82 1.52 

30 1.82 1.52 – – 

36 1.82 1.52 1.82 1.52 

97/3 Collector row dimensions when using flat roof stands 

B 

A 


B 

Sizing 5 

97/4 Installation dimensions of portrait wall mounting kits for 

Vaciosol CPC6 and CPC12 vacuum tube collectors (dimensions 

A and B ➔ 97/5) 

Number Collector row dimensions for Vaciosol 

of tubes 

CPC6 CPC12 

one row two rows one row two rows 

B = 2.10 m B=4.15m B=2.10m B=4.15m 

A A A A 

m m m m 

6 0.70 0.70 – – 

12 1.40 1.40 1.40 1.40 

18 2.15 2.15 – – 

24 2.85 2.85 2.80 2.80 

30 3.55 3.55 – – 

36 4.25 4.25 4.20 4.20 

97/5 Collector row dimensions when using rooftop installation kits 

A 

97

5 

Sizing 

5.4 Hydraulic system engineering 

5.4.1 Hydraulic circuit 

Collector array 

A collector array should consist of the same collectors 

and have the same collector orientation (all portrait or 

all landscape). This is necessary, since the volume flow 

distribution would otherwise be non-uniform. A 

maximum of ten Logasol SKN3.0 or SKS4.0 flat-plate 

collectors may be installed next to each other and 

hydraulically connected in a collector row if the 

connections are on alternate sides. If the connections 

are all on the same side, a maximum of five Logasol 

SKS4.0 flat-plate collectors can be installed next to 

each other and hydraulically connected. With CPC6 or 

CPC12 vacuum tube collectors, a maximum of 36 

tubes can be connected in series. 

Connection in series 

The hydraulic connection of collector rows in series is 

quickly accomplished because of the ease of 

connection. Connection in series is the easiest way to 

achieve a uniform volume flow distribution. An almost 

uniform flow through the individual collectors can be 

achieved, even if the collector rows are asymmetrically 

distributed. 

The number of collectors per row should be equal, if 

possible. However, the number of collectors in the 

individual rows must not differ by more than one. 

The maximum number of flat-plate collectors 

connected in series is limited to 9 or 10 collectors and 3 

rows (➔ 98/1). 

98 

Row(s) Max. number of 

collectors per row with 

flat-plate collectors 

In small systems it is preferable to connect collectors in 

series. Connecting the collectors in parallel is better in 

larger systems. This makes the volume flow 

distribution of the entire array more uniform. 

Connection in series Connection in parallel 

Max. number of tubes 

per row with vacuum 

tube collectors 

1 10 36 1 

2 5 18 2 

3 3 12 3 

4 

More than three rows 


not possible! 

98/1 Collector array layout options 

– 

Row(s) Max. number of collectors per 

row with flat-plate collectors 

With alternate connections 

max. 10 collectors per row 

or 

with connections on same side 

max. 5 SKS4.0 per row 

Allow for a higher pressure drop if Logasol SKS4.0 

collectors are connected in series (➔ 102/2). 

The hydraulic connection is shown in the following 

diagram on the example of a rooftop installation. 

Additional automatic air vent valves may be required 

if such valves cannot be installed above the top row 

(i.e. flat roof installation) (➔ page 119). As an 

alternative to the use of automatic air vent valves, the 

system can also be operated using an air separator in 

the cellar (separate or integrated into the Logasol 

KS01... compact station) if the system is filled via a 

filling station. 


4 

… 

… 

n 

Max. number of tubes 

per row with vacuum 

tube collectors 

Max. 36 tubes per row

Examples of connections in series 

E 

V 

E 

V 

FSK 

FSK 

99/1 Layout of a row of collectors 

99/2 Two collector rows connected in series 

E 

V 

1) 

E 

V 

99/3 Three collector rows connected in series 

R 

FSK 


1 to 10 collectors 

Logasol SKS4.0 Logasol SKS4.0 

Connection at alternate sides: 


1) 

1 to 5 collectors per row V R 1 to 5 collectors per row 


FSK 


per row 


1) 

R 

E 

V 

1) Kit for connecting in series 

1) 

1) 

R 


E 

1) 


FSK 


per row 

1) Kit for connecting in series 

R 

R 

FSK 

R 

E 

V 

V 

R 

FSK 


FSK 

Vaciosol CPC12 

12 to 36 tubes 

Same-side connection: 1 

to 5 collectors 


12 to 36 tubes 

in total 

V 

R 

Sizing 5 

FSK 

99

5 

Sizing 

Connection in parallel 

Connect the collector rows in parallel if more than 10 

flat-plate collectors or 36 tubes are required. Rows 

connected in parallel must consist of the same number 

of collectors and must be hydraulically connected in 

accordance with the Tichelmann principle. Ensure that 

the tube diameters are identical. Perform a hydraulic 

balancing if this is not possible. Provide a Tichelmann 

loop in the return to minimise heat losses. Collector 

arrays that are installed side by side can be arranged 

in a mirror image so that both arrays can be connected 

with a riser in the centre. 

E 

V 

E 

V 

100/1 Connecting collector rows in parallel 

100 

E 

E 

E 

E 

R 

R 

FSK 

FSK 


1 to 10 collectors per row 

Ensure that only collectors of one type are used, since 

portrait and landscape collectors have a different 

pressure drop value. 

Each row requires a separate automatic air vent valve. 

As an alternative to the use of automatic air vent 

valves (➔ page 119), the system can also be operated 

using an air separator in the cellar (separate or 

integrated into the Logasol KS01... compact station) if 

the system is filled via a Logasol BS01 filling station 

(➔ page 120). In this case, a shut-off valve is required 

for each flow in a row. 

Logasol SKS4.0 Logasol SKS4.0 

E 

FSK 

Connection at alternate sides: 


1) For improved ventilation and for calibrating the collector arrays 

install a shut-off ball valve in each outlet. 


V 

E 

E 

FSK 

1) 

1) 

1) 

R 


12 to 36 tubes per row 

Same-side connection: 


V R

Combined connection in series and in parallel 

It is only possible to hydraulically connect more than 

three collectors above or behind each other by using a 

combination of connection in series and connection in 

parallel. This is done by connecting the bottom two (1 

+ 2) and the top two (3 + 4) collectors in series 

(➔ 101/1). 

101/1 Connection of more than three landscape collectors above each other 

Collector array with dormer 

The following hydraulic schemes represent one option 

for solving the problem of dormers. These hydraulic 

schemes generally equate to two rows of collectors 

connected in series. Observe the information 

concerning the maximum number of collectors that 

can be used in rows of collectors connected in series. As 

E 

V 

R 

FSK 

E 

V 

E 

R 


Logasol SKN3.0-w 

FSK 

1) 

1) 

4 

3 

2 

1 

1) Kit for connection in series 

101/2 Hydraulic connection of collector arrays that are interrupted by a dormer 

E 


Sizing 5 

Then connect rows 1 + 2 to rows 3 + 4 in parallel. Here 

too, observe the position of the automatic air vent 

valve. 

➔ The maximum permitted number of collectors per 

row is 5 if two collector rows connected in series are 

connected to each other in parallel. 

➔ Take the pressure drop of the collector array into 

consideration when selecting the compact station. 

E 

V 

E 

R 

1) 

1) 

Logasol SKS4.0-w 

FSK 

an alternative to the use of automatic air vent valves, 

the system can also be operated using an air separator 

in the cellar (separate or integrated into the Logasol 

KS01... compact station) if the system is filled via a 

filling station. 

E 

4 

3 

2 

1 


Dormer Dormer 

R 

E 

V 

FSK 

101

5 

Sizing 

5.4.2 Flow rate in the collector array for flat-plate collectors 

The nominal flow rate for engineering small and 

medium-sized systems is 50 l/h per collector, resulting 

in a total system flow rate as per formula 102/1. 

➔ A flow rate 10% to 15% lower (at full pump rate) 

does not usually lead to significant yield reductions. 

However, avoid higher flow rates to minimise the 

amount of power required by the solar circuit pump. 

102 


VA Total system flow rate in l/h 

VK,Nom Nominal flow rate of collector in l/h 

nK Number of collectors 

5.4.3 Pressure drop calculation in collector array for flat-plate collectors 

Collector row pressure drop 

The pressure drop of a collector row increases with the 

number of collectors per row. The pressure drop for a 

row including connecting accessories, subject to the 

number of collectors per row, can be found in the table 

102/2. 

Number 

of 

collectors 

VA = VK,Nom ⋅ nK = 50 l/h ⋅ nK 102/1 Formula for total system flow rate 

➔ The pressure drop values for the Logasol SKS4.0 and 

SKN3.0 collectors for a solar fluid mixture consisting of 

50% glycol and 50% water at a mean temperature of 

50 °C are specified in the table 102/2. 

Pressure drop for a row consisting of n collectors 

Logasol SKN3.0 Logasol SKS4.0 

portrait landscape portrait and landscape 

at a flow rate per collector (nominal flow rate 50 l/h) 

50 l/h 100 l/h1) 150 l/h2) 50 l/h 100 l/h1) 150 l/h2) 50 l/h 100 l/h1) 150 l/h2) n mbar mbar mbar mbar mbar mbar mbar mbar mbar 

1 1.1 4.7 10.2 0.4 1.7 4.3 30 71 131 

2 1.5 6.5 13.2 1.9 6.9 14.4 31 73 133 

3 2.1 13.5 26.3 5.6 18.1 35.1 32 82 153 

4 6.5 22.1 – 9.3 29.7 – 39 96 – 

5 11.1 34.5 – 14.8 46.8 – 44 115 – 

6 15.2 – – 21.3 – – 49 – – 

7 21.0 – – 28.9 – – 61 – – 

8 28.0 – – 37.6 – – 73 – – 

9 35.9 – – 47.5 – – 87 – – 

10 45.0 – – 58.6 – – 101 – – 

102/2 Pressure drop values for collector rows with Logasol SKN3.0 or SKS4.0 including AAV and connection kit; pressure drop values apply to solar 

fluid L at an average temperature of 50 °C 

1) Flow rate per collector, connected in two rows (➔ page 103) 

2) Flow rate per collector, connected in three rows (➔ page 103) 

– Non-permissible number of collectors 


Rows of collectors connected in series 

The pressure drop of the array results from the total of 

all pipework drop values and the pressure drop for 

each row of collectors. The pressure drop of rows of 

collectors connected in series is cumulative. 

ΔpArray = pRow Δ ⋅ nRow 103/1 Formula for pressure drop of a collector array with rows of 

collectors connected in series 

As far as table 102/2 is concerned, take into 

consideration that the actual flow rate is calculated via 

the individual collectors connected in series from the 

number of collector rows and the nominal collector 

flow rate (50 l/h): 

VK = VK,Nom ⋅ nRow = 50 l ⁄ h ⋅ nRow 103/2 Formula for flow rate through a collector with rows of collectors 



ΔpArray Pressure drop for collector array in mbar 

ΔpRow Pressure drop for one collector row in mbar 

nRow Number of collector rows 

VK Flow rate through the individual collectors in l/h 


Example 


Sizing 5 


– Connection in series of 2 collector rows, each with 

5 Logasol SKN3.0-s solar collectors 

● Wanted 

– Pressure drop of overall collector array 

● Calculation 

– Flow rate through one collector: 

VK = VK,Nom · nRow V K =50l/h ·n Row =50l/h·2=100l/h 

– Read-off from table 102/2: 

34.5 mbar per collector row 

– Pressure drop of array: 

ΔpArray = ΔpRow · nRow =34.5mbar·2=69mbar 

➔ The pressure drop of the collector array is 69 mbar. 

E 

V 

R 

FSK 

103/3 Connection in series of two Logasol SKN3.0 collector rows 

103

5 

Sizing 

Collector rows connected in parallel 

The pressure drop for the array results from the total of 

the pipework pressure drop values up to a collector row 

and the pressure drop of an individual collector row. 

Unlike the situation when connecting in series, the 

actual flow rate via the individual collectors 

corresponds to the nominal collector flow rate (50 l/h) 






104 

ΔpArray = ΔpRow 

104/1 Formula for the pressure drop of a collector array with rows of 

collectors connected in parallel 

V K 

= 

V K,Nom 

104/2 Formula for the flow rate through a collector with rows of 

collectors connected in parallel 

Example 


– Connection in parallel of 2 collector rows, each 

with 5 Logasol SKN3.0-s solar collectors 

● Wanted 




VK = VK,Nom =50l/h 




ΔpArray = ΔpRow = 11.1 mbar 

➔ The pressure drop of the collector array is 11.1 mbar. 

104/3 Two Logasol SKN3.0 collector rows connected in parallel using 

the Tichelmann principle 


E 

V 

E 

FSK 

R


Illustration 105/3 shows an example of a combination 

of connections in series and in parallel. In each case, 

the top and bottom rows of collectors are connected in 

series to form a sub-array, meaning that only the 

pressure drop values of the sub-array collector rows 

connected in series will cumulate. 

For this, take into consideration that the actual flow 

rate is calculated via the individual collectors 

connected in series from the number of collector rows 

connected in series and the nominal flow rate per 

collector (50 l/h): 



Δpsub-array Pressure drop of the collector sub-array consisting of 

collector rows connected in series in mbar 



Nominal flow rate of collector in l/h 

V K,Nom 

ΔpArray = ΔpSub-array = pRow Δ ⋅ nRow 105/1 Formula for the pressure drop of a collector array consisting of 

a combination of collector rows connected in series and parallel 

VK = VK,Nom ⋅ nRow = 50 l ⁄ h ⋅ nRow 105/2 Formula for the pressure drop through a collector array 

consisting of a combination of collector rows connected in 

series and in parallel 

Example 


Sizing 5 


– Connection in parallel of 2 sub-arrays consisting 

of 2 rows of collectors, each of which consists of 5 

Logasol SKN3.0 solar collectors. 

● Wanted 




VK = VK,Nom · nRow V K =50l/h ·n Row =50l/h·2=100l/h 



– Pressure drop of (sub-)array: 

ΔpArray = ΔpSub-array = ΔpRow · nRow Δp Array =34.5mbar·2=69mbar 


E 

V 

E 

R 

FSK 

105/3 Combination of connections in series and in parallel in a 

collector array consisting of Logasol SKN3.0 solar collectors 

105

5 

Sizing 

5.4.4 Calculation of pressure drop values in an array of vacuum tube collectors 

Pressure drop of CPC6 and CPC12 vacuum tube collectors; heat transfer media; Tyfocor LS; medium 

temperature 40 °C 

106/1 Pressure drop of CPC6 and CPC12 vacuum tube collectors 

Collector array pressure drop 

The pressure drop of the array approximately consists 

of the total of the pressure drop values of each 

collector. The pressure drop values of the connecting 

lines may also need to be taken into consideration. 

106 

Δp 

mbar 

90 

80 

70 

60 

50 

40 

30 

20 

10 

CPC12 

0 

0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 5 

Δ = Δp ⋅ n 

p Array 

106/2 Formula for the pressure drop of a collector array 

I 

V 

min 

The flow rate through the individual collectors is 

calculated from the aperture area of the collector and 

the nominal collector flow rate (0.6 l/min · m 2 ). 



Δp Pressure drop for one collector in mbar 

n Number of collectors 

VK Flow rate through the individual collectors in l/min. 

VK,Nom Nominal flow rate of collector in l/min · m2 A Aperture areas in m 2 

ACPC6 = 1.28 m2 ACPC12 = 2.56 m2 Technical guide - Logasol solar technology for domestic hot water heating and central heating backup - 06/2007 

CPC6 

VK = 

VK,Nom ⋅ n⋅ A 

106/3 Formula for the flow rate through a collector

Example 1 


– 2 CPC12 connected in series 

● Wanted 

– Collector array pressure drop 



VK = VK,Nom · n · ACPC12 V K = 0.6 l/min · m 2 · 2 · 2.56 m 2 

V K =3l/min 

– Read-off from diagram 106/1: 

ΔpCPC12(3 l/min) =46mbar 


ΔpArray = ΔpCPC12(3 l/min) · n 

ΔpArray =46mbar·2 

ΔpArray =92mbar 


Example 2 


– 2 CPC12 and 1 CPC6 connected in series 

● Wanted 

– Collector array pressure drop 



VK = VK,Nom · n · ACPC6 + n · ACPC12 VK =0.6l/min · m2 · (1 · 1.28 m2 + 2 · 2.56 m2 ) 

VK =3.8l/min 

– Read-off from diagram 106/1: 

ΔpCPC6(3.8 l/min) =30mbar 

ΔpCPC12(3.8 l/min) =60mbar 


ΔpArray = ΔpCPC6(3.8 l/min) · n + ΔpCPC12(3.8 l/min) · n 

ΔpArray =30mbar·1+60mbar·2 

ΔpArray =150mbar 


Sizing 5 


107

5 

Sizing 

5.4.5 Pressure drop of pipework in the solar circuit 

Calculating the pipework 

The flow velocity in the pipework should be in excess of 

0.4 m/s to enable air remaining in the heat transfer 

medium to be transported to the next air separator in 

lines with a slope. Interfering flow noise can occur from 

flow velocities of 1 m/s and above. Take individual 

resistance values (caused by bends, for example) into 

consideration in the pressure drop calculation. In 

practice, this is often done by adding 30% to 50% to the 

Number 

of 

collecto 

rs 

108 

Flow 

rate 

pressure drop of the straight pipework. The actual 

pressure drops can vary more subject to the type of 

pipework. 

In systems with differently aligned collector arrays 

(east/west systems), take the total flow rate into 

consideration when the common flow line is being 

sized. 

Flow velocity v and pressure drop R in copper pipes with pipe dimensions of 

15 x 1 18 x 1 22 x 1 28 x 1.5 35 x 1.5 

v R v R v R v R v R 

l/h m/s mbar/m m/s mbar/m m/s mbar/m m/s mbar/m m/s mbar/m 

2 100 0.21 0.93 – – – – – – – – 

3 150 0.31 1.37 – – – – – – – – 

4 200 0.42 3.41 0.28 0.82 – – – – – – 

5 250 0.52 4.97 0.35 1.87 – – – – – – 

6 300 0.63 6.97 0.41 2.5 – – – – – – 

7 350 0.73 9.05 0.48 3.3 0.31 1.16 – – – – 

8 400 0.84 11.6 0.55 4.19 0.35 1.4 – – – – 

9 450 0.94 14.2 0.62 5.18 0.4 1.8 – – – – 

10 500 – – 0.69 6.72 0.44 2.12 – – – – 

12 600 – – 0.83 8.71 0.53 2.94 0.34 1.01 – – 

14 700 – – 0.97 11.5 0.62 3.89 0.4 1.35 – – 

16 800 – – – – 0.71 4.95 0.45 1.66 – – 

18 900 – – – – 0.8 6.12 0.51 2.06 0.31 0.62 

20 1000 – – – – 0.88 7.26 0.57 2.51 0.35 0.75 

22 1100 – – – – 0.97 8.65 0.62 2.92 0.38 0.86 

24 1200 – – – – – – 0.68 3.44 0.41 1.02 

26 1300 – – – – – – 0.74 4.0 0.45 1.21 

28 1400 – – – – – – 0.79 4.5 0.48 1.35 

30 1500 – – – – – – 0.85 5.13 0.52 1.56 

108/1 Flow velocity and pressure drop per meter of straight copper pipe for a 50/50 glycol:water mixture at 50 °C 


5.4.6 Pressure drop of the selected solar cylinder 

The pressure drop of the solar cylinder depends on the 

number of collectors and the flow rate The indirect coils 

of the solar cylinder have various pressure drop 

characteristics because of their differing dimensions. 

Numbe 

r of 

collect 

ors 

Flow 

rate 

SL300-1 

SL300-2 

SL400-2 

SL500-2 

SM300 

SM400 

SM500 

5.4.7 Selecting the Logasol KS... compact station 

The selection of the suitable complete station can be 

approximately determined through the number of 

collectors. The pressure drop (residual head) and the 

flow rate in the collector circuit are required for 

finalising the selection. Take the following pressure 

drop values into consideration: 


Sizing 5 

Use table 109/1 to estimate the pressure drop The 

pressure drop in the table applies to a 50/50 

glycol:water mixture at a temperature of 50 °C. 

Press drop in solar indirect coils of the Logalux cylinder 

P750 S PL750/2S PL1000/2S PL750 PL1000 PL1500 Duo 

FWS750 

● Pressure drop in the collector array (➔ page 102) 

● Pipework pressure drop (➔ page 108) 

Duo 

FWS1000 

l/h mbar mbar mbar mbar mbar mbar mbar mbar mbar mbar mbar 

2 100

5 

Sizing 

5.5 Sizing of the diaphragm expansion vessel 

5.5.1 System volume calculation 

The volume of a solar heating system with the Logasol 

KS... complete station is significant in the sizing of the 

expansion vessel and the determination of the 

quantity of solar fluid. 

The following formula applies to the filling volume of 

the solar heating system with a Logasol KS... complete 

station: 

110/1 Formula for filling volume of solar heating systems with a 

Logasol KS... complete station 


VA System filling volume 

VK Volume of one collector (➔ 110/3) 


VWT Solar indirect coil volume (➔ 110/4) 

VKS Volume of a Logasol KS… complete station (approx. 1.0 l) 

VR Pipework volume (➔ 110/2) 

Solar indirect coil volume 

110 

VA = VK ⋅ nK + VWT + VKS + VR Pipework volume 

Pipe dimension 

Ø × wall thickness 

Specific line volume 

mm l/m 

15×1.0 0.133 

18×1.0 0.201 

22×1.0 0.314 

28×1.5 0.491 

35×1.5 0.804 

42×1.5 1.195 

110/2 Specific filling volume of selected pipework 

Solar collector volume 


Solar collectors Collector content 

Type Version l 

Flat-plate 

collector 

SKN3.0 

portrait 

landscape 

0.86 

1.25 

High-perf. flatplate 

collector 

. 

SKS4.0 

portrait 

landscape 

1.43 

1.76 

Vacuum tube CPC6 6 tubes 0.97 

collector CPC12 12 tubes 1.91 

110/3 Filling volume of Logasol solar collectors 

Solar cylinder Indirect coil content 

Scope Type Logalux l 

DHW heating 

DHW heating and 

central heating backup (combi cylinder) 

Thermal store 

dual-mode 

mono-mode 

110/4 Filling volume of solar indirect coils in Logalux cylinders 

SM300 8.0 

SM400 9.5 

SM500 13.2 

SL300-2 0.9 

SL400-2 1.4 

SL500-2 1.4 

SL300-1 0.9 

SU160 4.5 

SU200 4.5 

SU300 8.0 

SU400 12.0 

SU500 16.0 

SU750 23.0 

SU1000 28.0 

P750 S 16.4 

PL750/2S 1.4 

PL1000/2S 1.6 

Duo FWS750 11.0 

Duo FWS1000 13.0 

PL750 2.4 

PL1000 2.4 

PL1500 5.4

5.5.2 Diaphragm expansion vessel for solar heating systems with flat-plate collectors 


Inlet pressure 

Adjust the inlet pressure of the diaphragm expansion 

vessel (DEV) prior to filling the solar heating system to 

take the system elevation into account. The require 

system inlet pressure be calculated using the following 

formula: 

Calculation parameters (➔ 111/1) and picture legend (➔ 111/2) 

pV DEV inlet pressure in bar 

hstat Static height in m between centre of DEV and highest point of 

system 

➔ The minimum inlet pressure is 1.2 bar. 

Filling pressure 

The expansion vessel creates a "hydraulic seal" when 

the system is filled, since an equilibrium between the 

fluid pressure and the gas pressure occurs at the 

diaphragm. The hydraulic seal (VV ➔ 111/4) is 

introduced with the system in a cold state, and 

monitored via the filling pressure at the system 

pressure gauge on the water side after venting and 

degassing the system in a cold state. The system filling 

pressure should be 0.3 bar higher than the DEV inlet 

pressure. A controlled evaporation temperature of 

120 °C is therefore reached in the event of stagnation. 

The filling pressure is calculated using the following 

formula: 


p0 DEV filling pressure in bar 

pV DEV inlet pressure in bar 

Hydraulic seal 

V V 

pV = 0.1 ⋅ hstat + 0.4 bar 

111/1 Formula for inlet pressure of a diaphragm expansion vessel 

p0 = pV + 0.3 bar 

111/3 Formula for filling pressure of a diaphragm expansion vessel 

➔ A deviation from the optimum inlet pressure or 

filling pressure always leads to a reduction in the 

available volume. This can cause system 

malfunctions. 

111/2 Inlet pressure of a diaphragm expansion vessel 


p V 

V V 

111/4 Filling pressure of a diaphragm expansion vessel 

p 0 

Sizing 5 

111

5 

Sizing 

Final pressure 

At the maximum collector temperature, the filling gas 

is compressed to the final system pressure by taking up 

additional expansion volume (Ve ➔ 112/2). 

The final pressure of the solar heating system and 

therefore the pressure rating and the required size of 

the DEV are determined by the safety valve response 

pressure. The final pressure is determined using the 

following formula: 

112/1 Formulas for final pressure of a diaphragm expansion vessel 

subject to the safety valve response pressure 


pe DEV final pressure in bar 

pSV Safety valve response pressure in bar 

Ve Expansion volume 

Hydraulic seal 

V V 

Intrinsic safety of a solar heating system 

A solar heating system is considered to be intrinsically 

safe if the DEV can absorb the volume change as a 

result of solar fluid evaporation in the collector and the 

connecting lines (stagnation). If a solar heating system 

is not intrinsically safe, the safety valve responds 

during stagnation. Then the solar heating system has 

to be re-started. A DEV is sized on the basis of the 

following assumptions and formulae: 


Vn,min Minimum D volume in l 

VA n 

System filling volume in l (➔ 110/1) 

Expansion coefficient (= 7.3 % with Δϑ = 100 K) 

VD Evaporation volume in l 

pe DEV outlet pressure in bar 

p0 DEV filling pressure in bar 


Volume of one collector (➔ 110/3) 

V K 

112 

pe ≤ pSV ∠ 0.2 bar for pSV ≤ 3 bar 

pe ≤ 0.9 ⋅ pSV for pSV > 3 bar 

V V + V e 

112/2 Final pressure of a diaphragm expansion vessel 

V n min 


p e 

( + 1) 

, = ( VA ⋅ n + VD) ⋅ ---------------------- 

( ∠ ) 

112/3 Formula for minimum DEV volume 

VD = 

nK ⋅ VK 112/4 Formula for the evaporation volume 

pe pe p 0


Sizing 5 

Nomograph for the graphical determination of the diaphragm expansion vessel for solar 

heating systems with flat-plate collectors 

The size of the diaphragm expansion vessel in systems 

with a 6 bar safety valve can be determined 

graphically subject to the system configuration using 

the following nomograph. The above assumptions and 

formulae are based on this nomograph. 

Sizing example 

● Specified solar heating system with 

– 4 Logasol SKS4.0-s collectors and Logalux SL400 

thermosiphon cylinders 

– 12 m single pipe length between collector array 

and cylinder 

– Pipe dimension 15 mm x 1.0 mm 

– Static height between DEV and the highest point 

of system = 10 m 

● Wanted 

– Required expansion vessel 

➔ The graphical determination of the diaphragm 

expansion vessel is described in the nomograph on 

pages 114 and 115. 

Item Calculation principles and initial values Required operation 

1 

2 

3 

4 

5 

The single pipe between the cylinder and the collector array is 

12 m in length. 

Trace the "Single pipe length" axis at 12 m horizontally to the left 

of the "Pipe dimensions" sub-diagram. 

The pipe dimension that was used is 15 x 1. Continue vertically upwards into the "DHW cylinder" subdiagram 

at the intersection with line 15 x 1. 

A Logalux SL400 DHW cylinder is specified for this system. At the intersection with the "Logalux SL..." curve, go horizontally 

to part 2 of the nomograph into the "Collector filling volume" 

sub-diagram. 

The system is operated using 4 Logasol SKS4.0-s collectors. The 

filling volume V K of the collector array is 5.72 l. 1) 

The static height between the highest point in the system 

(automatic air vent valve) and the expansion vessel is 10 m. 

Draw an additional line parallel to the existing lines for a filling 

volume of 5.72 l in the "Collector array filling volume" subdiagram. 

Go vertically down into the "static height" sub-diagram 

from the intersection point with the new line 

At the intersection with line 10, go horizontally left and read off 

the minimum nominal volume of the expansion vessel (11.5 l). 

Result: Allow for a DEV with 18 l (DEV 10, white field). 

113/1 Description of operations for the example of expansion vessel sizing with nomograph (➔ 114/1 and ➔ 115/1) 

1) The values in table ➔ 110/3 apply to the collector filling volume 

113

5 

Sizing 

Nomograph for sizing the diaphragm expansion vessel for solar heating systems with flat-plate collectors 

(part 1) 

114 

28 x 1.5 

Logalux SM500, Duo FWS1000 

Duo FWS750 

Logalux SM400 

Logalux SM300 

Logalux PL1500 

Logalux P750 S 

Logalux SL..., PL.../2S, PL750, PL1000 

114/1 Nomograph for sizing the expansion vessels for systems with the Logasol KS... complete station and 6 bar safety valve (part 2 ➔ 115/1) with 

sizing example highlighted in blue (description ➔ page 113) 


22 x 1 

18 x 1 

15 x 1 

0 

2 

4 

6 

8 

10 

12 

14 

16 

18 

20 

22 

24 

26 

28 

30

Sizing 5 

Nomograph for sizing the diaphragm expansion vessel for solar heating systems with flat-plate collectors 

(part 2) 

Minimum nominal DEV volume (V n,min in l) 

0 

10 

20 

30 

MAG 18 

MAG 25 

MAG 35 

3 4 5 6 7 8 9 10 12 15 20 25 30 35 40 

MAG 80 

115/1 Nomograph for sizing the expansion vessel for systems with the Logasol KS... complete station and 6 bar safety valve with sizing example 

highlighted in blue (description ➔ page113) 

≤ 8 

10 

12 

14 

MAG 100 


MAG 35 

MAG 50 

≤ 8 

10 

12 

14 

25 

30 

35 

40 

45 

50 

55 

60 

65 

70 

75 

80 

85 

90 

Static height (h st in m) Collector array filling volume (V K in l) 

115

5 

Sizing 

5.5.3 Diaphragm expansion vessel for solar heating systems with vacuum tube collectors 

Allow for a 6 bar safety valve to protect the solar 

heating circuit. Check the suitability of the envisaged 

components for this pressure level. Install the 

System example: Solar DHW heating 

116/1 System example (abbreviations ➔ page 148) 

Calculation principles for determining the expansion vessel size 

The following formulae are based on a 6 bar safety 

valve. To calculate the expansion vessel size 

accurately, first determine the system component 

capacities so that the expansion vessel size can be 

calculated using the following formula: 


VNom Nominal expansion vessel size 

VA System filling volume (content of entire solar heating circuit) 

VVapour Capacity of collectors and pipework 

in the vapour area above the bottom edge of collector 

DF Pressure factor (➔ 117/1) 


– 2 CPC12 collectors 

– Cu pipe: 15 mm, length = 2 x 15 m 

– Static height: H = 9 m 

– Content of the cylinder indirect coil and the solar 

heating station: e. g. 6.4 l 

– Cu pipe in vapour area: 15 mm, length = 2 x 2 m 

– VA : 14.21 l 

116 

FSK 

VS 

RS 

Logalux SM... (SL...) 

VNom ≥ 

( VA ⋅ 01 , + VVapour ⋅ 1. ( 25) 

) ⋅ DF 

116/2 Formula for the nominal size of the expansion vessel 

min 2 m 

expansion vessel 20 to 30 cm above the compete 

station in the returning to protect the group from 

excessive temperatures. 

0.2–0.3 m 

– V Vapour: 4.35 l 

The system component contents can be found in tables 

➔ 110/2 to 110/4. 

The pipework above the bottom edge of the collector 

(the lowest collector, if there are several collectors) can 

contain vapour when the solar heating system is idle. 

The vapour volume VVapour therefore includes the 

contents of the pipework and collectors concerned. 

Calculating the size of the expansion vessel 

VNom ≥ (VA ·0.1 + VVapour · 1.25) · DF 

DF (9 m) = 2.77 (➔ 117/1) 

VNom ≥ (14.21 l · 0.1 + 4.35 l · 1.25) · 2.77 

VNom ≥ 19 l 

➔ Select the next bigger expansion vessel, i.e. 25 l 

Calculation of system content, inlet pressure and 

operating pressure 

Add the hydraulic seal of the relevant expansion vessel 

to the system content to determine the necessary 

amount of solar fluid. 

The hydraulic seal in the expansion vessel results from 

filling the solar heating system from the inlet pressure 

to the operating pressure (subject to static height "H"). 


PSS 

Logasol 

KS01..

The percentage of the hydraulic seal in relation to the 

selected vessel size and the specified pressure can be 

found in table 117/1. 

with a static height of 9 m, the following applies: 

Vseal = VNom ·Hydraulic seal factor 

Hydraulic seal factor (9 m) = 7.7 % (➔ 117/1) 

Vseal = 25 l ·77%= 25 l ·0.77 

Vseal = 1.9 l 

Determining the pressure factor 


Sizing 5 

Calculation of the required amount of solar fluid 

Vtot = VA + VSeal Vtot = 14.21 l + 1.9 l 

Vtot = 16.13 l 

Calculation basis for determining the pre-cooling vessel size 

Install a pre-cooling vessel upstream of the expansion 

vessel to provide the expansion vessel with thermal 

protection, particularly with solar central heating 

backup, and systems for DHW heating with more than 

60% coverage. 

Result 

The expansion vessel with 25 l capacity is adequate. 

The inlet pressure is 2.6 bar, the operating pressure is 

2.9 bar and the solar fluid content is 16.13 l. 

Static height H Pressure factor DF Hydraulic seal factor DEV inlet pressure System filling pressure 

m % bar bar 

2 2.21 9.4 1.9 2.2 

3 2.27 9.1 2.0 2.3 

4 2.34 8.8 2.1 2.4 

5 2.41 8.6 2.2 2.5 

6 2.49 8.3 2.3 2.6 

7 2.58 8.1 2.4 2.7 

8 2.67 7.9 2.5 2.8 

9 2.77 7.7 2.6 2.9 

10 2.88 7.5 2.7 3.0 

11 3.00 7.3 2.8 3.1 

12 3.13 7.1 2.9 3.2 

13 3.28 7.0 3.0 3.3 

14 3.43 6.8 3.1 3.4 

15 3.61 6.7 3.2 3.5 

16 3.80 6.5 3.3 3.6 

17 4.02 6.4 3.4 3.7 

18 4.27 6.3 3.5 3.8 

19 4.54 6.1 3.6 3.9 

20 4.86 6.0 3.7 4.0 

117/1 Determining the pressure factor 

Pre-cooling vessel size 5 12 

l l 

Height mm 270 270 

Diameter mm 160 270 

Connection Inch 2 x R6 2 x R6 

Max. operating 

pressure: 

bar 

10 10 

117/2 Pre-cooling vessel specification 

The following standard value applies with regard to 

the pre-cooling vessel size: 

VPre ≥ 

VVapour ∠ VPipe 117/3 Formula for nominal pre-cooling vessel size 


VPre Nominal pre-cooling vessel size 

VVapour Content of collectors and pipework 

in the vapour area above the bottom edge of the collector 

VPipe Pipework from the lower edge of the collector to 

the complete station 

117

6 

Design/engineering information regarding the installation 

6 Design/engineering information regarding the installation 

6.1 Pipework, thermal insulation and collector temperature sensor extension cable 

Glycol and temperature-resistant sealing 

All components of a solar heating system (including 

flexible seals for valve seats, diaphragms in expansion 

vessels etc.) must be made from glycol-resistant 

materials and carefully sealed, since water:glycol 

mixtures have a greater tendency to leak than pure 

water. Aramide fibre seals have proven to be effective. 

Graphited cord is suitable for sealing glands. Hemp 

seals must also be coated with temperature-resistant 

and glycol-resistant thread paste. Nissen products "Neo 

Fermit universal" or "Fermitol" can be used as thread 

paste (observe the manufacturer's instructions). 

The solar hose ferrules on the Logasol SKN3.0 collectors 

and the connectors of the Logasol SKS4.0 collectors 

provide an easy and reliable seal for collector 

connections. Connecting kits for Twin-Tube 15 and 

Twin-Tube DN20 are available for providing a reliable 

connection to the special Twin-Tube double tube. 

Pipework routing 

All connections in the solar circuit must be brazed. 

Alternatively, press fittings can be used, provided that 

they are suitable for use with a water:glycol mixture 

and respectively high temperatures (200 °C). All 

pipework must be routed with a rise towards the 

collector array or the air vent valve, if installed. Heat 

expansion must be taken into consideration when the 

pipework is being routed. The pipes must be equipped 

118 

Pipe diameter 

mm 

Twin-Tube (double tube) 

insulation thickness 1) mm 

Collector temperature sensor extension lead 

When routing the pipework, also route a two-core lead 

(up to 50 m length 2 × 0.75 mm2 ) for the collector 

temperature sensor alongside. An appropriate lead is 

provided in the insulation of the special Twin-Tube. 

Provide a shield for the collector temperature sensor 

Aeroflex SSH pipe 

diameter × insulation 

thickness mm 

118/1 Thickness of thermal insulation for solar heating system connection lines. 

1) Requirements according to the Energy Saving Order (EnEV) [Germany] 

with expansion facilities (bends, sliding clamps, 

compensators) to prevent damage and leaks. 

➔ Plastic pipework and galvanised components are 

not suitable for solar heating systems. 

Thermal insulation 

Connection lines may be routed in unused flues, air 

shafts and wall slits (in new buildings). Open shafts 

must be suitably sealed to prevent heat loss caused by 

rising air (convection). 

The thermal insulation of the connection lines must be 

designed for the operating temperature of the solar 

heating system. Therefore use appropriate high 

temperature-resistant insulating materials such as 

insulating hoses made from EPDM rubber. The 

thermal insulation must be UV and temperatureresistant 

in external areas. The connection kits for the 

Logasol SKS4.0 solar collectors are fitted with UV and 

high temperature-resistant thermal insulation made 

from EPDM rubber. The solar collectors, complete 

stations and solar cylinders made by Buderus are fitted 

with efficient thermal insulation in the factory. 

The table 118/1shows standard values for the 

insulating thickness on pipework in solar heating 

systems. Mineral wool is unsuitable for external 

applications because it absorbs water and then fails to 

provide thermal insulation. 

Aeroflex HT pipe 

diameter × insulation 

thickness mm 

extension lead, if it is routed together with a 230 V 

cable. Install the FSK collector temperature sensor near 

the flow header in the sensor lead pipe of the Logasol 

SKN3.0 and SKS4.0 collectors. 


Mineral wool insulation 

thickness (in relation to 

λ =0.035W/m⋅K) 1) mm 

15 15 – 15 × 24 20 

18 – 18 × 26 18 × 24 20 

20 19 22 × 26 22 × 24 20 

22 – 22 × 26 22 × 24 20 

28 – 28 × 38 28 × 36 30 

35 – 35 × 38 35 × 36 30 

42 – 42 × 51 42 × 46 40

6.2 Air vent valve 

Design/engineering information regarding the installation 6 

6.2.1 Automatic air vent valve 

Unless "filling station and air separator" are being 

used (➔ page 120), solar heating systems with flatplate 

collectors are ventilated via quick-acting air vent 

valves at the highest point of the system. After filling 

has been completed, this valve must be closed to 

prevent gaseous solar fluid from escaping from the 

system in the event of stagnation. Vent Vaciosol 

vacuum collector tubes with "filling station and air 

separator". 

Provide an air vent valve at the highest point of the 

system (detail E ➔ 119/1) and, for every change of 

direction, with a new rise (e.g. in dormers, ➔ 101/2). 

If there are several rows of collectors, provide an air 

vent valve for each row (➔ 119/2), unless the system 

can be ventilated above the top row (➔ 119/3). Order 

an automatic all-metal air vent valve in the form of an 

air vent valve kit. 

➔ Never use air vent valves with plastic floats in solar 

heating systems because of the high temperatures that 

occur. If there is insufficient room for an automatic allmetal 

air vent valve with an upstream ball valve, 

provide a manual air vent valve with a drip container. 

Logasol SKN3.0 Logasol SKS4.0 

R V 

E FSK 

E 

119/1 Hydraulic diagram with air vent valve at the highest point of 

system 

119/2 Hydraulic diagram with air vent valve for each collector row on 

the example of flat roof installation (connection in series) 

119/3 Hydraulic diagram with air vent valve above the top row on the 

example of rooftop installation (connection in series) 


FSK 

Same-side 

connection 

E E 

R V 

R V 

E 

E 

R V 

119

6 


6.2.2 Filling station and air separator 

A solar heating system can also be filled with the 

Logasol BS01 filling station (➔ 120/1), resulting in a 

large proportion of the air being pushed out of the 

system during the filling procedure. An air vent valve 

on the roof is not required in this case. Instead, a 

central air separator is part of the Logasol KS01 2branch 

complete station. (➔ 120/2). This separates the 

residual micro-bubbles out of the medium during 

operation. 

Benefits of the system are: 

● Reduced installation effort because no air vent 

valves are required on the roof 

● Easy and quick commissioning, i.e. filling and 

ventilation in one step. 

● Efficiently vented system 

● Low-maintenance operation 

If the collector array consists of several rows connected 

in parallel, provide each individual row with a shut-off 

valve in the flow. Each row is filled and ventilated 

individually during the filling procedure. 

120 

No air 

vent valve 

required 

1 

A 

2 

1 Pressure hose 5" 

2 Return hose 6" 

FSK 

PSS 

Logasol 

KS01.. 

Collector 

120/1 Logasol BS01 filling station 

VS2 AW 

120/2 System design; detail A: Filling procedure with filling pump (seal ➔ 60/1; abbreviations ➔ page 148) 


FSX 

FSS 

PS 

M1 

RS2 

VS1 

M2 

RS1 

EZ 

EK 


HK1 

WWM 

PZ 

FK 


Oil/Gas 

1 

2 

Logamatic 

4121 

+ FM443


6.3 Information regarding the different flat-plate collector installation systems 

6.3.1 Permissible standard snow loads and building heights in accordance with DIN 1055 

The following table contains the permissible standard 

snow loads and building heights for the different 

installation options. Observe the information shown 

Roof cover/wall 

Permissible roof pitch 

Permissible building heights 

(wind loads) of up to 20 m - at 

wind speeds of up to 80 mph 

Permissible building heights 

(wind loads) of up to 100 m - at 

wind speeds of up to 94 mph 

Standard snow loads in 

accordance with DIN 1055, part 

5 

0–2 kN/m 2 

Standard snow loads in 

accordance with DIN 1055, part 

5 

> 2kN/m2 6.3.2 Selection aid for hydraulic connection accessories 

Provide suitable hydraulic connection accessories 

subject to the number of collectors and their hydraulic 

connections. 

Single-row collector array 


Portrait/landscape 

Tiles, plain tiles, slate, 

shingle, corrugated 

sheets, sheet steel, 

bitumen 

25°–65°, 

5°–65° (corrugated 

sheets, sheet steel roof) 

Connecting two collector rows in parallel 

during engineering to safeguard a correct installation 

and to prevent damage to the collector array. 

Roof integration 


Tiles, plain tiles, slate, 

shingle 

25°–65° 

Without accessories Without accessories 

Only portrait collectors 

with rooftop installation 

kit 

Not permissible 

Flat roof installation 


➔ For further details regarding the various assembly 

systems, see the relevant "Hydraulic connection" 

section in the following sub-chapters. 


Wall mounting 45–60 

°C, landscape 

– load-bearing 

0° (with slightly sloping 

roofs of up to 25°, 

protection from sliding 

off or on-site fixing) 

Without accessories 

(observe securing flat 

roof supports!) 

With flat roof support kit 

(observe flat roof 

support fixing!) 

– 

Without accessories 


Without accessories Without accessories Without accessories Without accessories 

Only portrait collectors 

with rooftop installation 

kit up to 3.1 kN/m 2 

Without accessories up 

to 3.8 kN/m 2 

121/1 Permissible standard snow loads and building heights in accordance with DIN 1055 

Without flat roof 

support kit up to 

3.8 kN/m 2 

Number of 

collectors 

Number of rows Connection kit Air vent valve kit1) 1 to 10 1 1 1 

121/2 Hydraulic connection accessories for a single-row collector array 

1) The air vent valve kit is not required if the system is filled with a "Filling station" (➔ page 120) 


Number of 

collectors 

Number of rows Connection kit Air vent valve kit 1) 

2 to 20 2 2 2 

121/3 Hydraulic connection accessories for connecting two collector rows in parallel 

1) The air vent valve kit is not required if the system is filled with a "Filling station" (➔ page 120). Also provide a shut-off valve in the flow 

of each row if the collectors are connected in parallel 

121

6 


Several collector rows connected in series 

122 

Number of 

collectors 

Number of rows Number 

of collectors 

per row 

Connection kit Air vent valve kit 1) 

122/1 Hydraulic connection accessories for connecting several collector rows in series 

1) The air vent valve kit is not required if the system is filled with a "Filling station" (➔ page 120). Additional air vent valve kits are required 

unless the system can be vented above the top row (e.g. with flat roof installation, ➔ 119/2). 


Series connection kit 

2 2 1 1 1 1 

3 

2 

2 

1 

1 1 1 

3 1 1 1 2 

4 2 2 1 1 1 

5 2 

6 

7 2 

3 

2 

1 1 1 

2 3 1 1 1 

3 2 1 1 2 

4 

3 

1 1 1 

8 2 4 1 1 1 

9 

2 

5 

4 

1 1 1 

3 3 1 1 2 

10 2 5 1 1 1


6.3.3 Rooftop installation for flat-plate collectors 


The collectors are secured at the same angle as the 

pitched roof using the rooftop installation kit. The roof 

skin retains its sealing properties. 

The rooftop installation kit for Logasol SKN3.0 and 

SKS4.0 flat-plate collectors consists of a standard kit for 

the first collector in a row and an extension kit for each 

additional collector in the same row (➔ 124/1). Use the 

rooftop installation extension kit only in conjunction 

with a standard kit. In place of the single-side collector 

tensioner (item. 1 ➔ 124/1) the extension kit contains 

so-called double-sided collector tensioners (item 5 

Roof connection for tile and plain tile covers 

9 

50 – 80 

33 

285 

Roof hook Rafter anchor 

Roof connection for slate and shingle covers 

Special roof hook 

Roof connection for corrugated sheets, sheet steel roof 

123/1 Roof connection versions for different roof covers (dimensions in mm) 

62 

40 

➔ 124/1) and connectors for defining the correct 

spacing and securing two adjacent Logasol SKN3.0 or 

SKS4.0 flat-plate collectors. 

Roof connections for different roof covers 

The profile rails and collector tensioners of the various 

rooftop installation kits are identical for all roof 

connections. The various installation kits for tile and 

plain tile, slate and shingle cover as well as for 

corrugated sheet and sheet steel roofs only differ with 

regard to the type of roof hook (➔ 123/1) or special 

fixing materials used (➔ 125/2, 125/1 and 126/2). 

10 

61 65 8 65 

M12 


35 

164.6 304 

55 

180 

300 

8 

75 

∅9 

38 – 59 

407 

35 70 

9 

123

6 


Roof connection for tiled roofs 

Fig. 124/1 shows an example of the rooftop 

installation kits for tiled covers. The roof hooks (123/1 

and item 2 ➔ 124/1) are hooked over the existing roof 

battens (➔ 124/2) and fastened to the profile rails. 

As an alterative to being hooked on, the roof hooks can 

also be fastened to a batten or a hard surface 

(➔ 124/3). This is done by turning the lower part of the 

roof hook. If additional height compensation is 

required, the lower section of the roof hook can be 

shimmed. 

When rooftop installation on a tiled roof is envisaged, 

check whether the dimensions specified in fig. 124/1, 

detail A must be complied with. Use the roof hooks 

supplied, if they 

● fit into the valley of the roof tile and 

● extend over the roof tile plus roof batten. 

➔ The tile cover should not exceed 120 mm. Where 

necessary, include a roofing contractor in the planning 

process. 

Caption (➔ 124/1) 

1 Single-sided collector tensioner (only in the standard kit) 

2 Roof hook, adjustable 

3 Profile rail 

4 Anti-slippage protection for collectors (2x per collector) 

5 Two-sided collector tensioner (only in the extension kit) 

6 Connector (only in the extension kit) 

7 Hard surface (cladding) 

Caption (➔ 124/2) 

1 Hexagon nut 

2 Serrated washer 

3 Roof batten 

4 Roof hook, lower part 

Caption (➔ 124/3) 

1 Hexagon nut 

2 Serrated washer 

3 Fixing screws 

4 Roof hook, lower part 

5 Rafter/hard surface 

124 

124/1 Rooftop installation standard kit and extension kit (highlighted 

in blue) for one Logasol SKN3.0 or SKS4.0 flat-plate collector 

(detail A: dimensions in mm) 

124/2 Hooked-on roof hook 

124/3 Roof hook fastened to the rafter 


7 

6 

35 

A 

5 

5 

50–86 

4 

B 

3 

4 

1 

2 

1 

2 

3 

4 

1 

2 

3


Plain tile roof connection 

Fig. 125/1 shows the attachment of the roof hook 

(item 2) to a plain tile cover. Trim and attach the plain 

tiles on site. 

The horizontal profile rails must be fastened to the roof 

hook in the same way as they are with tiles (➔ 124/1). 

➔ Refer to a roofing contractor for rooftop installation 

on plain tiles, if required. 

Caption (➔ 125/1) 

1 Plain tiles (cut along the dotted line) 

2 Roof hook, lower part fastened to a rafter or plank/board 

Roof connection with slate or shingle 

➔ Special roof hook installations with slate or shingle 

cover must be carried out by a roofing contractor. 

Fig. 125/2 shows an example of a waterproof 

installation of the special roof hooks (item 5 ➔ 125/2) 

on a slate or shingle cover with seals and flashing to be 

provided on site. 

The horizontal profile rails must be fastened to the 

special roof hooks in the same way as they are with tile 

cover (➔ 124/1). 

Caption (➔ 125/2) 

1 Sheet steel above special roof hook (on site) 

2 Sheet steel below special roof hook (on site) 

3 Multiple overlap 

4 Seal (on site) 

5 Special roof hook 

6 Screw (standard delivery) 

125/1 Roof hook attached on a plain tile roof 


1 

2 

6 

4 

5 

4 

125/2 Special roof hook with waterproof cover for attaching a rooftop 

installation kit for flat-plate collectors to a slate or shingle cover 

3 

1 

2 

125

6 


Roof connection in roofs with insulation on rafters 

Fig. 126/1 shows the roof connection to a roof with 

insulation on rafters using the special hooks. The 

roofing contractor must secure a wooden board with a 

minimum cross-section of 28 mm x 200 mm to the 

rafter. The force that is introduced by the roof hook 

must be transferred by this board to the load-bearing 

rafters. With an assumed maximum snow load of 

2kN/m 2 (without accessories) or 3.1 kN/m 2 (with 

accessories), the following force per roof hook must be 

allowed for: 

● Horizontal to roof Fsx = 0.8kN 

● Vertical to roof Fsy =1.8kN 

The horizontal profile rails must be fastened to the 

special roof hooks in the same way as they are with a 

tile cover (➔ 124/1). 

Caption (➔ 126/1) 

1 Roof tile 

2 Special roof hook 

3 Insulation on rafters 

4 Rafter 

5 On-site screw connection 

6 Wooden board (at least 28 mm × 200 mm) 

F sx Load per roof hook, vertical to the roof 

F sy Load per roof hook, horizontal (parallel) to the roof 

Roof connection with corrugated sheet roofs 

➔ Rooftop installation onto a corrugated sheet cover is 

only permissible if the headless spiral screws can be 

fastened at least 40 mm into a wooden structure with 

adequate load-bearing capacity (➔ 126/2). 

The corrugated sheet roof connection contains 

headless spiral screws including retaining brackets and 

sealing washers that are used instead of the roof hooks 

in the rooftop installation kit. 

Fig. 126/2 shows how the profile rails are attached to 

the retaining brackets of the headless spiral screws. 

Caption (➔ 126/2) 

1 M8 × 16 Allen screws 


3 Retaining bracket 

4 Hexagon nut 

5 Seal washer 

126 

126/1 On-site attachment of additional wooden boards on the 

insulation on rafters, to which the special hooks for attaching 

a rooftop installation kit are fastened (dimensions in mm) 


5 

6 

1 

6 

5 2 

1 

4 

3 

2 

1 

126/2 Example of profile rail attachment with rooftop installation on 

a corrugated sheet cover (dimensions in mm) 

105 

< 60 

F sy 

2 

3 

F sx 

4 

3 

4 

5 

3 

> 40


Roof connection on roofs with sheet steel 

Fig. 127/1 shows the roof connection on a sheet steel 

roof with the corrugated sheet/sheet steel roof 

connection Secure a sleeve to the roof on site and make 

it watertight. Generally four sleeves per collector are 

usually soldered on for this purpose. The M12 × 180 

headless special screws are fastened to the substructure 

(rafter or load-bearing timber, at least 

40 mm × 40 mm) through the sleeve. 

Caption (➔ 127/1) 


2 M8 × 16 Allen screws 

3 Retaining bracket 

4 M12 headless special screw 

5 Sleeve 

6 Sheet steel roof 

7 Sub-structure (timber, at least 40 mm × 40 mm) 

Snow load profile/additional rail 

Also install a snow guard and an additional rail 

(accessories) during the rooftop installation of portrait 

flat-plate collectors on buildings between 20 m and 

100 m in height in regions with snow loads of 2 kN/m 2 

to 3.1 kN/m 2 . These provide better distribution of the 

higher loads on the roof. 

Fig. 127/2 shows the installation of a snow guard and 

an additional rail on the example of tile cover. Both 

accessories can also be fitted to installation systems for 

other roof covers. 

Caption (➔ 127/2) 

1 Profile rails from rooftop installation kit 

2 Additional rails (including collector tensioner) 

3 Additional roof connection (snow guard standard delivery) 

4 Vertical profile rails (snow guard standard delivery) 

1 

6 

127/1 On-site attachment of sleeves for watertight mounting of 

headless special screws for rooftop installation on sheet steel 

cover (dimensions in mm) 


2 

3 

4 

105 

40 

5 

< 60 

127/2 Rooftop installation kit with snow guard and additional rail 

6 

7 

4 

5 

3 

7 

> 40 

1 

2 

3 

4 

1 

127

6 


Water connections 

The rooftop connection kits are used to make the 

hydraulic collector connections during rooftop 

installation (figs 128/1 and128/2). 

Roof outlets are required for flow and return, since the 

collector connections are above roof level. A 

ventilation tile (as shown in fig. 128/3) can be used as 

a roof outlet for the flow and return lines. The flow line 

is routed through the roofing skin with an incline to 

the air vent valve, if installed, via the upper ventilation 

tile. The lead from the collector temperature sensor 

also runs through this tile. Route the return line with a 

slope to the KS station. A ventilation tile can be used 

for this if the return line runs through the roof below or 

at the same level as the collector array return 

connection (fig. 128/3). An additional air vent valve is 

not usually required, in spite of the change of direction 

in the tile. 

➔ Involve a roofing contractor in the planning to 

prevent damage to the building. 

Caption (➔ 128/1) 

1 Connecting line 1000 mm 

2 Dummy plug 

3 Spring clips 

4 Hose coupling with R 3/4” connection or 18 mm locking ring 

Caption (➔ 128/2) 

1 1000 mm connection line with R 3/4“ connection or 18 mm 

locking ring at the system side, insulated 

2 Dummy plug 

3 Clip 

Caption (➔ 128/3) 

1 Flow line 

2 Return line 

3 Sensor lead 

4 Ventilation tile 

5 Air vent valve 

Static requirements 

➔ The rooftop installation kit is exclusively designed 

for the secure mounting of solar collectors. The 

attachment of other rooftop equipment such as aerials 

to the rooftop mounting kit is not permissible. 

The roof and the substructure must have an adequate 

load-bearing capacity. A load of about 50 kg or 55 kg 

can be expected for each Logasol SKN3.0 or SKS4.0 flat- 

128 

128/1 SKN3.0 rooftop connection kit 

128/2 SKS4.0 rooftop/roof integration connection kit 

128/3 Route connection lines beneath the roof 

plate collector. Also take the specific regional loads as 

per DIN 1055 [or local regulations] into account. 

The values in table 121/1 are the permissible standard 

snow loads and building heights for rooftop 

installation. 


1 

4 

3 

2 

2 

3 

3 

3 

3 

2 

4 5 

2 

3 

3 

1 

3 

2 

3 

3 

1 

4 

1 

4 

3 

1


Rooftop installation system component selection aid 

Include appropriate connecting materials in the 

engineering subject to the number of collectors and 

their hydraulic connections. 

SKN3.0-s 

and 

SKS4.0-s 

SKN3.0-w 

and 

SKS4.0-w 

Total number of collectors 2 3 4 5 6 7 8 9 10 

Number of rows 1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

Number of collectors per row 2 1 3 2 1 4 2 5 3 6 3 2 7 4 8 4 9 5 3 10 5 

1 

2 

3 

4 

Standard 

kit1) Tiles 

Tiles 

Plain tiles 

Slate 

Shingle 

Corrugated 

sheets 

Sheet steel roof 

1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

Extension kit1) Tiles 

Tiles 

Plain tiles 

Slate 

Shingle 

Corrugated 

sheets 

sheet steel roof 

1 – 2 1 – 3 2 4 3 5 4 3 6 5 7 6 8 7 6 9 8 

Additional kit 

Standard kit2) Tiles 

Tiles 

Plain tiles 

Slate 

Shingle 

Corrugated 

sheets 


1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

Additional kit 


Tiles 

Plain tiles 

Slate 

Shingle 

Corrugated 

sheets 


1 – 2 1 – 3 2 4 3 5 4 3 6 5 7 6 8 7 6 9 8 

Standard 

kit1) Tiles 

Tiles 

Plain tiles 

Slate 

Shingle 

Corrugated 

sheets 


1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 


Tiles 

Plain tiles 

Slate 

Shingle 

Corrugated 

sheets 


1 – 2 1 – 3 2 4 3 5 4 3 6 5 7 6 8 7 6 9 8 

1) Consisting of installation kit and roof connection 

2) Consisting of snow guard and additional horizontal rail, required for snow loads of 2 kN/m2 to 3.1 kN/m2 129/1 Fixing materials for rooftop installation system 

and building heights of 20 m 

to 100 m 


129

6 


6.3.4 Roof integration for flat-plate collectors 

The roof integration system is suitable for SKN3.0 and 

SKS4.0 portrait and landscape collectors. Individual 

installation kits are available for tile, shingle, slate and 

plain tile roof covers. The collectors seal the roof in 

conjunction with the metal surround (coated 

aluminium, anthracite RAL 7016). 

The two outer collectors in a row are installed using a 

standard kit. Every other collector in the array is 

installed between the two outer collectors using an 

extension kit (fig. 130/2). 

Fit additional roof battens on site for attaching the 

collectors, the metal surround and as support for the 

cover plate at the top and the flashing at the bottom 

(fig. 130/3). 

During installation the collectors are first attached to 

the roof battens and then encased in the metal 

surround. The hydraulic connection lines can be 

routed through the roof inside the side cover plates. 

Another row consisting of the same number of 

collectors can be installed directly above the first row. 

Appropriate standard and extension kits are available 

for an additional row. The space between the top and 

bottom collector rows is closed off with a cover plate 

(fig. 131/1). 

If two rows with a different number of collectors are 

installed above each other, leave a gap of at least two 

rows of tiles between each row. 

➔ If necessary, include a roofing contractor in the 

planning and installation to prevent damage to the 

building. 

Caption (➔ 130/2) 

1 Top left cover plate 

2 Top centre cover plate 

3 Top right cover plate 

4 Retainer 

5 Right side cover plate 

6 Bottom right cover plate 

7 Batten to prevent slippage 

8 Anti-slippage protection (with landscape: 5x) 

9 Bottom centre cover plate 

10 Bottom left cover plate 

11 Roll of sealing tape 

12 Left side cover plate 

13 Left support plate 

14 Double-sided hold-down retainer 

15 Cover strip 

16 Screw 6 x 40 with washer 

17 Single-sided hold-down retainer 

18 Right support plate 

Caption (➔ 130/3) 

1 Additional roof battens 

130 

130/1 General layout, collector array integrated into the roof 

130/2 1 standard kit for the two outer collectors and 1 extension kit 

for the centre collector (highlighted in blue) 

130/3 Spacing between additional roof battens for single-row 

installation (dimensions in mm); values in brackets for portrait 

version 


11 

12 

1 

4 

13 

10 9 8 7 6 

1 

1 

1 2 3 

1 

15 

14 

1 

16 

17 

18 

160 200 - 230 

1860 - 1890 (940 - 970) 

2120 (1200) 

2240 - 2270 (1320 - 1350) 

2490 - 2520 (1570 - 1600) 

1 

5 

4



The roof integration connection kits are recommended 

for making the hydraulic collector connections during 

roof integration installation (figs 131/2 and 131/3). 

The flow and return lines can be routed through the 

roof inside the side cover plate using the connection 

kits. 

If an air vent valve is installed, route the flow line 

beneath the roof with an incline. Route the return line 

to the KS station with a slope. 



snow loads and building heights for roof integration. 

Caption (➔ 131/1) 

1 Centre cover plate (right) 

2 Rubber lip 

Caption (➔ 131/2) 

1 Connection line 1000 mm 

2 Bracket 

3 Clamping disk 

4 Nut G1 

5 Spring clip 

6 Dummy plug 

7 Hose ferrule with R 3/4“ connection or 18 mm locking ring 

Caption (➔ 131/3) 

1 1000 mm connection line with R 3/4“ connection or 18 mm 

locking ring at the system side, insulated 

2 Dummy plug 

3 Clip 

131/1 Cover plate between two rows of collectors arranged one above 

the other 


2 

5 

2 

1 

131/2 SKN3.0 roof installation connection kit 

3 

2 

6 

3 4 

131/3 SKS4.0 roof installation connection kit 

5 

5 

7 

3 

2 

5 

3 

1 

4 3 

1 

6 

5 

2 

1 

5 

3 

1 

7 

131

6 


Roof integration installation system component selection aid 

Include appropriate fixing materials in the 


rows. 

132 

SKN3.0-s 

and 

SKS4.0-s 

SKN3.0-s 

and 

SKS4.0-s 

Total number of collectors 1 2 3 4 5 6 7 8 9 10 

Number of rows 1 1 2 1 3 1 2 1 1 2 3 1 1 2 1 3 1 2 

Number of collectors per row 

Row 1 

Tiles 

Tiles 

1 2 1 3 1 4 2 5 6 3 2 7 8 4 9 3 10 5 

Row 1 

Slate 

Shingle 

1 – 1 – 1 – – – – – – – – – – – – – 

Individual Plain tiles 

installation Additional row 

Tiles 

Tiles 

Additional row 

Slate 

Shingle 

Plain tiles 

Row 

Tiles 

Tiles 

– – 1 – 2 – – – – – – – – – – – – – 

Row 1 

Slate 

Shingle 

– 1 – 1 – 1 1 1 1 1 1 1 1 1 1 1 1 1 

Standard kit Plain tiles 

for 2 collectors Additional row 

Tiles 

Tiles 


Slate 

Shingle 

Plain tiles 

Row 1 

Tiles 

Tiles 

– – – – – – 1 – – 1 2 – – 1 – 2 – 1 

Row 1 

Slate 

Shingle 

Plain tiles 

– – – 1 – 2 – 3 4 1 – 5 6 2 7 1 8 3 

Extension kit 


Tiles 

Tiles 


Slate 

Shingle 

Plain tiles 

– – – – – – – – – 1 – – – 2 – 2 – 3 

132/1 Fixing materials for roof integration installation system 


SKN3.0-w 

and 

SKS4.0-w 

SKN3.0-w 

and 

SKS4.0-w 


Total number of collectors 1 2 3 4 5 6 7 8 9 10 

Number of rows 1 1 2 1 3 1 2 1 1 2 3 1 1 2 1 3 1 2 

Number of collectors per row 1 2 1 3 1 4 2 5 6 3 2 7 8 4 9 3 10 5 

Individual 

installation 

Standard kit 

for 2 collectors 

Extension kit 

Row 1 

Tiles 

Tiles 

Row 1 

Slate 

Shingle 

Plain tiles 


Tiles 

Tiles 


Slate 

Shingle 

Plain tiles 

Row 1 

Tiles 

Tiles 

Row 1 

Slate 

Shingle 

Plain tiles 


Tiles 

Tiles 


Slate 

Shingle 

Plain tiles 

Row 1 

Tiles 

Tiles 

Row 1 

Slate 

Shingle 

Plain tiles 


Tiles 

Tiles 


Slate 

Shingle 

Plain tiles 

132/1 Fixing materials for roof integration installation system 

1 – 1 – 1 – – – – – – – – – – – – – 

– – 1 – 2 – – – – – – – – – – – – – 

– 1 – 1 – 1 1 1 1 1 1 1 1 1 1 1 1 1 

– – – – – – 1 – – 1 2 – – 1 – 2 – 1 

– – – 1 – 2 – 3 4 1 – 5 6 2 7 1 8 3 

– – – – – – – – – 1 – – – 2 – 2 – 3 


133

6 


6.3.5 Flat roof installation for flat-plate collectors 

Flat roof installation is intended for level roof surfaces. 

However, it is also suitable for roofs with minor slopes 

of up to 25° (➔ 134/1). For this, secure the flat roof 

support on site. 

The flat roof installation kit for Logasol SKN3.0 and 

SKS4.0 flat-plate collectors consists of a standard kit for 

the first collector in a row and an extension kit for each 

additional collector in the same row (➔ 134/2). 

Accessories are required for buildings more than 20 m 

high and with snow loads of > 2kN/m 2 (➔ 121/1). 

The angle of inclination of the flat roof support can be 

adjusted in steps of 5° as follows: 

● Portrait flat roof support: 30° to 60° (adjustable by 

25° by trimming the telescopic rail) 

● Landscape flat roof support: 35° to 60° (adjustable 

by 25° or 30° by trimming the telescopic rail) 

The flat roof supports can be fixed to the roof by means 

of weighting (ballast) or by attaching them to the roof 

structure. 

On-site mounting 

The flat roof supports can by mounted on on-site 

substructures consisting of double-T supports, for 

example (➔ 134/3). For this, there are holes in the 

bottom profile rails of the flat roof supports. The on-site 

substructure must be designed such that the wind force 

acting upon the collectors can be absorbed. 

The support spacing dimensions can be found in 

figures 135/1 to 135/3. The positions of the holes for 

attaching the flat roof supports to the on-site 

substructure can be found in figure 134/3. 

For buildings more than 20 m in height or with snow 

loads of 2 kN/m 2 to 3.8 kN/m 2 , each standard kit for 

portrait collectors must be fitted with an additional rail 

(standard kit addition) and each extension kit must be 

fitted with an additional rail and an additional 

support (extension kit addition). With landscape 

collectors, fit all installation kits with an additional rail 

(standard kit and extension kit addition). 

134 

134/1 Examples of actual flat-plate collector angle of inclination when 

using flat roof supports on a flat roof with a shallow pitch (< 25°) 

Item 1: pitch; item 2: collector angle of inclination 

134/2 Flat roof support standard kit and extension kit (blue) for one 

SKN3.0-s or SKS4.0-s flat collector 

134/3 Flat roof support fixed on site with base anchoring to a 

substructure consisting of double-T supports (dimensions in m); 

value in brackets for landscape version; centre contact surface 

(blue) only required for buildings above 20 m in height. 


30˚ 

45˚ 

15˚ 15˚ 

45˚ 

2 

30˚ 

0.563 0.563 

(0.353) (0.353) 

1


0.98 

135/1 Collector support spacing in standard version with flat roof supports for portrait collectors SKN3.0-s and SKS4.0-s (dimensions in m) 

135/2 Collector support spacing in standard version when using additional supports with flat roof supports for portrait collectors SKN3.0-s and 

SKS4.0-s (dimensions in m) 

135/3 Distance between collector supports with flat roof supports for landscape SKN3.0-w and SKS4.0-w collectors (dimensions in m) 

1.17 

0.98 0.19 0.98 0.19 

1.82 0.275 


0.98 

1.82 

0.98 

135

6 


Securing by means of ballast troughs 

Four ballast troughs are required for each flat roof 

support when the collectors are weighed down 

(dimensions: 950 mm x 350 mm x 50 mm) - these are 

hooked into the flat roof support (➔ 136/1). They are 

filled with concrete slabs, gravel or the like to weigh 

them down. See table 137/1 for the required ballast 

weight (maximum 320 kg with gravel filling) subject 

to the height of the building. 

With a building up to 20 m high and snow loads of up 

to 2 kN/m2 , one additional support is required for the 

4th, 7th and 10th collector in a row when ballast 

troughs are used in conjunction with portrait 

collectors. The installation kit includes one additional 

support when landscape collectors are used. The 

additional supports are required for hooking in the 

trays. 

For buildings higher than 20 m or with snow loads of 

2kN/m 2 to 3.8 kN/m 2 , each standard kit must include 

an additional rail (standard kit addition) and each 

extension kit for portrait collectors must include an 

additional support and an additional rail (extension 

kit addition). With landscape collectors, all installation 

kits must be equipped with an additional rail 

(standard kit and extension kit addition). 

Erect the entire structure on protective building mats to 

protect the skin of the roof. 


The flat roof connection kits are used to make the 

hydraulic collector connections during flat roof 

installation (fig. 136/2 and 136/3). Route the flow line 

parallel to the collector to prevent damage to the 

connection due to the movement of the collector in the 

wind (fig. 136/4). 



snow loads and building heights. 

Caption (➔ 136/2) 

1 Bracket with R 3/4“ connection on the system-side 

or 18 mm locking ring 

2 Clamping disk 

3 Nut G1 

4 Dummy plug 

5 Spring clips 

Caption (➔ 136/3) 

1 Bracket with R 3/4“ connection on the system side or 18 mm 

locking ring 

2 Dummy plug 

3 Clip 

Caption (➔ 136/4) 

1 Pipe clamp (on site) 

2 M8 thread 

3 Bracket (connection kit standard delivery) 

4 Flow line 

136 

136/1 Flat roof support with ballast trough and additional guy ropes 

136/2 SKN3.0 flat roof connection kit 

136/3 SKS4.0 flat roof connection kit 

136/4 Collector flow line routing 


1 

3 

2 

2 

4 

3 

5 

2 

3 

4 

3 

3 

5 

1 

2 

4 

3 2 

1 

3 

1 

1


Flat roof support weights 

When the roof loads are being determined, the 

following weights can be assumed for flat roof 

installation kits: 

● Standard kit, portrait: 12.2 kg 

● standard kit, landscape: 8.7 kg 

Flat roof support fixing (collector stabilisation) 

Flat roof installation system, component selection aid 




● Extension kit, portrait: 7.2 kg 

● Extension kit, landscape: 8.7 kg 

Building height Wind velocity Base anchoring Ballast Guy rope 

Number and type of 

screws 1) 

Weight (e.g. 

concrete slabs) 

Protection against 

tilting 

Weight (e.g. concrete 

slabs) 


Protection against 

slippage 

Max. tensile strength 

per rope 

m km/h kg kg kN 

0 to 8 102 2x M8/8.8 270 180 1.6 

8 to 20 129 2x M8/8.8 450 320 2.5 

20 to 100 2) 

151 3x M8/8.8 – 450 3.3 

137/1 Options for securing flat roof supports for each collector to prevent tilting and sliding as a result of wind; version for Logasol SKN3.0 and 

SKS4.0 flat-plate collectors 

1) Per collector support 

2) Additional rail and additional support required for portrait collectors, and additional rail for landscape collectors 

Installation kits with ballast trough 1) 

SKN3.0-s 

and 

SKS4.0-s 


Number of rows 1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

Number of collectors per row 2 1 3 2 1 4 2 5 3 6 3 2 7 4 8 4 9 5 3 10 5 

1 

2 

3 

4 

Standard kit 1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

Extension kit 1 – 2 1 – 3 2 4 3 5 4 3 6 5 7 6 8 7 6 9 8 

Additional support 2) 

– – – – – 1 – 1 – 1 – – 2 1 2 2 2 2 – 3 2 

Standard kit addition 3) 

1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

Addition to extension kit3) 1 – 2 1 – 3 2 4 3 5 4 3 6 5 7 6 8 7 6 9 8 

Standard kit 1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

SKN3.0-w 

and 

SKS4.0-w 

Extension kit 

Standard kit addition 

1 – 2 1 – 3 2 4 3 5 4 3 6 5 7 6 8 7 6 9 8 

3) 1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

Addition to extension kit 3) 

1 – 2 1 – 3 2 4 3 5 4 3 6 5 7 6 8 7 6 9 8 

Installation kits for on-site attachment 

SKN3.0-s 

Standard kit 1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

and Extension kit 1 – 2 1 – 3 2 4 3 5 4 3 6 5 7 6 8 7 6 9 8 

SKS4.0-s Standard kit addition3) 1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 


SKN3.0-w 

Standard kit 1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

and Extension kit 1 – 2 1 – 3 2 4 3 5 4 3 6 5 7 6 8 7 6 9 8 

SKS4.0-w Standard kit addition 3) 

1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 


1) The standard installation and extension kits contain one set of ballast troughs each 

2) Not required if the additional extension kit is selected 

3) Required in addition to the standard and extension kit with snow loads in excess of 2 kN/m2 137/2 Fixing materials for the flat roof installation system 

or building height exceeding 20 m 

137

6 


6.3.6 Wall installation for flat-plate collectors 

Wall installation is only suitable for landscape Logasol 

SKN3.0-w and SKS4.0-w flat-plate collectors, and is 

only approved for building walls up to an installation 

height of 20 m. 

Wall mounting requires horizontal flat roof supports. 

The first collector in the row is installed using a wall 

support standard kit. Every additional collector in the 

same row is installed using a wall support extension 

kit. These kits include three supports (➔ 138/2). 

The pitch of the collectors on the wall may only be set 

to between 45° and 60° relative to the horizontal 

(➔ 138/1). 

On-site fixing 

Secure the collector supports on site to a load-bearing 

surface using three bolts per support (➔ 138/3). 



snow loads and building heights. 

138 

0.353 

0.353 

138/1 Max. permitted collector pitch on a wall 

Item 1: pitch (absolute angle relative to the horizontal) 

Item 2: collector angle of inclination 

138/2 Wall mounting with wall support standard kit and wall support extension kit (blue); dimensions in m 

Wall construction 1) 

Reinforced concrete at least B25 

(min. 0.12 m) 

Reinforced concrete at least B25 

(at least 0.12 m) 

Steel substructure 

(e.g. double-T support) 

0.98 0.98 0.135 0.98 0.98 

138/3 Fixing materials 

1) Brickwork on request 

2) Each dowel/screw must be able to withstand a tensile force of at least 1.63 kN and a vertical force (shearing force) of at least 1.56 kN 

3) 3x screw diameter = external washer diameter 


60˚ 

30˚ 

Screws/dowels for each collector support Distance from edge of wall 

3x UPAT MAX Express-anchors, type MAX 8 (A4) 2) and 

3x washers3) in acc.with DIN 9021 

3x Hilti HST-HCR-M82) or HST-R-M82) and 


3x M8 (4.6) 2) and 


45˚ 

m 

2 

>0.10 

>0.10 

– 

1 

45˚


Component selection aid for wall mounting system for Logasol SKN3.0-w and SKS4.0-w 




Installation kits 

SKN3.0-w and 

SKS4.0-w 


Number of rows 1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 


2 1 3 2 1 4 2 5 3 6 3 2 7 4 8 4 9 5 3 10 5 

per row 

1 

2 

3 

4 

Standard kit for wall 

mounting 

Extension kit 

for wall mounting 

139/1 Fixing materials for wall mounting system for Logasol SKN3.0-w and SKS4.0-w 

6.3.7 Standard values for installation times 

Use of contractors 

At least two installers must be allowed for when 

installing solar collectors. Each installation on a 

sloping roof involves intervention in the roof cover 

Source appropriate contractors (roofers, plumbers) 

prior to installation. Use these as required. Buderus 

provides training in the installation of solar heating 

systems. Information concerning this can be obtained 

from your local Buderus sales office (➔ back). 

➔ Kits are available for any installation option, 

including accessories and installation instructions. 

Read the installation instruction for the chosen 

installation option carefully before work commences. 

1 2 1 2 3 1 2 1 2 1 2 3 1 2 1 2 1 2 3 1 2 

1 – 2 1 – 3 2 4 3 5 4 3 6 5 7 6 8 7 6 9 8 

Collector installation times 

The times in table 139/2 only apply to collector 

installation with installation systems and connections 

to a row of collectors. In-depth knowledge of the 

relevant installation instructions is required. 

The times for safety measures, transporting the 

collectors and installation systems to the roof and roof 

modifications (adapting and cutting the roof tiles) are 

not taken into consideration. These times should be 

estimated in consultation with a roofing contractor. 

➔ The time calculation for planning a solar collector 

system is based on practical experience. These depend 

on the on-site situation. The actual installation times 

on site may therefore vary considerably from the times 

quoted in table 139/2. 

Installation option and scope Standard values for installation times 

of 2 SKN3.0/SKS4.0 collectors for each additional collector 

Rooftop installation 1.0 h per installer 0.3 h per installer 

Roof integration 3.0 h per installer 1.0 h per installer 

Flat roof installation with ballast troughs 1.5 h per installer 0.5 h per installer 

Flat roof installation on substructures 1.5 h per installer 0.5 h per installer 

Wall mounting 45° 2.5 h per installer 1.5 h per installer 

139/2 Installation times with two installers for collectors in small systems (up to 8 collectors) on roofs with an angle of inclination of ≤ 45°, 

excluding handling time, effort in conjunction with safety precautions and the creation of on-site substructures 


139

6 


6.4 Flat roof installation for vacuum tube collectors 

Flat roof installation is intended for level roof surfaces. 

The area required for concrete slabs must be cleared of 

gravel on flat roofs with gravel cover. 

Place protective building mats beneath the concrete 

slabs on flat roofs with plastic roof membranes (item 1 

➔ 140/2) 

Vacuum 

Concrete slab spacing 

tube collector 

with 30° with 45° 

A B B 

m m m 

CPC6 0.55 1.225 0.915 

CPC12 1.100 1.225 0.915 

140/1 Concrete slab spacings when using flat roof supports 

Weight of concrete slabs 

140 

Building height Vacuum 

tube collector 

Number 

of angled frames 

140/2 flat roof supports with concrete slabs (dimensions A and B 

➔ 140/1) 

Item 1: Protective building mats for flat roofs with plastic roof 

membranes 

Angle 

of frame 


A 

1 

B 

Required weight 

front concrete slab rear concrete slab 

m kg kg 

0 to 8 

CPC6 

CPC12 

2 

2 

30°/45° 

30°/45° 

75 

75 

75 

75 

between 8 and 20 

CPC6 2 30°/45° 112 112 

CPC12 2 30°/45° 112 112 

140/3 Required concrete slab weight when using flat roof supports


6.5 Lightning protection and earth bonding for solar heating systems 

Requirement for lighting protection 

The requirement for lightning protection is defined in 

the building regulations of the country concerned. 

Lightning protection is frequently required for 

buildings that 

● are more than 20 m high 

● are significantly higher than the surrounding 

buildings 

● are valuable buildings (monuments) and/or 

● could cause panic if a lightning strike occurred 

(schools, etc.). 

If a solar heating system is installed on top of a 

building with a high protection target (e.g. high-rise 

building, hospital, assembly buildings or shops) the 

lightning protection requirements should be discussed 

with an expert and/or the building operator. This 

discussion should take place in the planning phase of 

the solar heating system. 

Since solar heating systems are not higher than the 

roof ridge (even in special cases), the probability of a 

direct lightning strike for a residential building in 

accordance with DIN VDE 0185, part 100, is the same 

with or without a solar heating system. 

Earth bonding for the solar heating system 

Irrespective of whether a lightning protection system is 

present, the flow and return of a solar heating system 

must always be earthed with a copper cable with at 

least 6 mm2 cross-section at the earth bonding rail. 

➔ If a lightning protection system is installed, 

determine whether the collector and the installation 

system are outside the protection scope of this system. 

If this is the case, a specialist electrical contractor 

must connect the solar heating system to the existing 

lightning protection system. Electrically conducting 

parts of the solar heating circuit must be earthed with 

a copper cable with at least 6 mm 2 cross-section at the 

earth bonding rail 


141

7 

Regulations and Directives 

7 Regulations and Directives 

Fax enquiry – Solar heating system for detached houses and two-family houses (Page 1/2) 

Details regarding the sizing of a solar heating system 

Project 

Contact Buderus Design/Engineering 

Mr./Mrs. Mr./Mrs. 

Telephone Telephone 

Fax Fax 

Place of collector installation 

System location: 

Collector orientation: 

Available roof area: 

Questionnaire "Fax inquiry - solar heating system for detached houses and two-family homes“ (copy template) 

142 

Postcode 

Town 

Point of the compass Angle of inclination 

Include scale drawings of southern aspect! 

Are collectors shaded? No Yes 

Type of collector installation: Roof integration 


Roof skin make-up: 

Solar heating system pipework 

Single line length in the system: 

Boiler room / installation room of the cylinder(s) 

Room dimensions: 

Smallest door size: 

Utilisation of solar energy 

90 

West 

Length 

Flat roof installation 

m 

m 

Outside 

the building 

m 

DHW (WW) 

+ – 

0 

South 

Height 

Length 

Height 

Swimming pool (S) 

90 

East 

Collektor model: SKN3.0 SKS4.0 

Vaciosol CPC 

Static height: 

m 

m 

m 

× Width 

Wall mounting 

× Width 

× Width 


m 

Between the highest system point and the 

centre of the diaphragm expansion vessel 

+ 

m 

Inside 

the building 

Central heating (H) 

m 

m 

Assumptions 

if no details 

are provided 

0 south 

No 

Adequate space 

Rooftop 

Tiled roof 

1 m / 8 m 

8 m 

> 2 m 

Adequate space 

2.00 m × 1.20 m 

DHW (WW)

Fax enquiry – Solar heating system for detached houses 

and two-family homes (Page1/2) 

DHW heating 

No. of occupants: persons 

Daily DHW demand: 

(Standard values in litres/person) 

Daily DHW volume: 

Washing machine with hot fill? No Yes 

Dishwasher with hot fill? No Yes 

DHW draw-off temperature: ˚ßC 

Max. cylinder temperature: ˚ß˚C 

Control ON 1 OFF 1 

Regulations and Directives 7 

litre (person × litres per person) 

DHW circulation: DHW circulation loss: W 

Time 

Reheating 

: 


4 persons 

50 l per person 

200 litres 

Reheating in summer mode? No Yes, with Yes, with … 

Boiler efficiency (summer mode): % 

50 % 

Additional cylinder volume? litre 

Dual-mode Mono-mode no 

Fuel: 

Central heating back-up 

Set water temperature: 

Oil Gas LPG Biomass Elec. District heating 

Operating period: From to 

Standard outside temperature: ˚˚ß˚C 

Flow temperature: ˚˚ß˚C Return temperature: 

Heating limit temp. (changeover to summer mode): ˚ß˚C 

Annual oil consumption: m3 l/p.a. 

Annual gas consumption: 

/p.a. 

Swimming pool water heating 

Type: 

Indoor 

Available boiler output: kW 

Boiler efficiency of: % 

Heat demand: kW 

˚ß˚C 

No 

No 

45 ˚ßC / 60 ˚ß˚C 

60 ˚˚ßC 

None 

None 

18 kW 

Fuel oil / 

Natural gas 

–14 ßC 

6 kW 

18 ˚ßC 

1260 l/p.a. / 

1160 m 3 /p.a. 

Private Public Private 

kW m3 HE output (for reheating): HE water content: 

/h 

˚ß˚C 

90 % 

35 / 30 ˚ ßC 

May – September 

Indoor pool 

Sheltered 

Pool cover: None Available Type of cover Available 

Reheating by boiler via heat exchange (HE)? Yes No, with … Yes, with HE … 

Date: Signature: 

Low Medium High 

(40 l/person) (50 l/person) (75 l/person) 

ON 2 OFF 2 ON 3 OFF 3 

: : : : : 

Outdoor Exposed Sheltered Sheltered from wind 

Tile colour 

(Std. value: 45 ß˚C For detached and two-family homes, 

60 ˚˚ßC for apartment buildings) 

Assumptions 

(continued) 

Basin: (Length x Width x Depth) m × m × 

m 

Please state! 

Blue 

24 ßC 

Please state! 

143

7 

Appendix 

Keyword index 

A 

Absorber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4–6, 8 

Accessories 

Fixing materials . . . . . . . . . . . . . . . . .129, 132, 137, 139 

Hydraulic connection (options) . . . . . . . . . . . . . . . . .121 

Accident prevention regulations . . . . . . . . . . . . . . .59 

Air separator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120 

Air vent valve . . . . . . . . . . . . . . . . . . . . . . . . . . .57, 119 

Angle of inclination (collectors) . . . . . . .82–83, 92, 95 

B 

Boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58 

Buffer bypass circuit . . . . . . . . . . . . . . . . . . . . . . . . .41 

C 

Central heating backup 

Buffer bypass circuit . . . . . . . . . . . . . . . . . . . . . . . . . .41 

RW return temperature limiter . . . . . . . . . . . . . . . . . .55 

Sample system . . . . . . . . . . . . . . . . . . . . . 64–69, 73–75 

Collector 

See solar collector... 

Collector array 

Collector row pressure drop . . . . . . . . . . . . . . .102, 106 

Flow rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102 

Hydraulic connection (options) . . . . . . . . . . . . . . . . . .98 

Number of collectors (sizing) . . . . . . . 80–81, 84–85, 89 

Pressure drop for connection in parallel . . . . . . . . . . .104 

Pressure drop with connection in series/parallel . . . .105 

Pressure drop, connection in series . . . . . . . . . . . . . .103 

Vacuum tube connector pressure drop . . . . . . . . . . .106 

Collector array hydraulics with dormer . . . . . . . . .101 

Collector temperature sensor extension lead . . . .118 


Pressure drop and flow rate . . . . . . . . . . . . . . . . . . . .105 

Computer simulation (solar heating system sizing) 79 

Connection accessories (hydraulic) . . . . . . . . . . . .121 

Connection in parallel . . . . . . . . . . . . . . . .98, 100, 104 

Connection in parallel and in series . . . . . . . .101, 105 

Connection in series . . . . . . . . . . . . . .98–99, 101, 103 

Connection in series and in parallel . . . . . . . .101, 105 

Connection pipes . . . . . . . . . . . . . . . . . . . . . . . . . .118 

Correction factor, number of collectors . . . . . . . . . .82 

Cylinder 

See dual-mode thermosiphon cylinder Logalux SL... 

See Duo FWS... combi cylinder 

See Logalux P750 S... combi cylinder 

See Logalux PL... thermosiphon thermal store 

See Logalux PL.../2S... thermosiphon combi cylinder 

144 

See Logalux SM... dual.mode cylinder 


D 

Daily heating . . . . . . . . . . . . . . . . . . . . . . . . . . . 87, 89 

DHW circulation line . . . . . . . . . . . . . . . . . . . . . . . . 54 

DHW heating 

Correction factor, number of collectors . . . . . . . . . . . 82 

Sample system . . . . . . . . . . . . . . . . . . . . . . . . . . . 70–72 

Sizing (apartment block with 3 to 5 residential units) . 87 

Sizing (apartment block with up to 30 residential units) . 

88– . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 

Sizing (detached house/two-family home) . . . 80, 82–83 

DHW heating and central heating backup 

Sample system . . . . . . . . . . . . . . . . . . . . . 64–69, 73–75 

Sizing (detached house/two-family home) . . . . . . 84, 86 

DHW mixer (thermostatic) . . . . . . . . . . . . . . . . 52–54 

Diaphragm expansion vessel (DEV) 111–112, 116–117 

Directives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 

Domestic hot water heating 

Sample system . . . . . . . . . . . . . . . . . . . . . . . . . . . 60–63 

Dormer (collector array hydraulics) . . . . . . . . . . . . 101 

Double-Match-Flow . . . . . . . . . . . . . . . . . . . . . . . . . 28 

Dual-mode cylinder Logalux SM... 

DHW circulation line . . . . . . . . . . . . . . . . . . . . . . . . . 54 

Dimensions and specification . . . . . . . . . . . . . . . . . . . 13 

Pressure drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 

Sample system . . . . . . . . . . . . . . . . . . 60–61, 64, 70–75 

Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83, 86 

Dual-mode thermosiphon cylinder Logalux SL... 

Design and function . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

DHW circulation line . . . . . . . . . . . . . . . . . . . . . . . . . 54 


Pressure drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 

Sample system . . . . . . . . . . . . . . . . . . 60–61, 64, 70–75 

Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83, 86 

Duo FWS... combi cylinder 



Pressure drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 

Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 

E 

Earth bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 

Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5, 8, 11 

EMS 

Boiler with EMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 

Control unit selection aid . . . . . . . . . . . . . . . . . . . . . . 27 

Solar function module FM443 . . . 28–29, 31, 41–43, 46 

Solar function module SM10 . . . . . . . . . . . . . 28–29, 46 

Energy supply (solar) . . . . . . . . . . . . . . . . . . . . . . . . . 3

F 

Filling pressure (DEV) . . . . . . . . . . . . . . . . . . . . . . .111 

Filling station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120 

Final pressure (DEV) . . . . . . . . . . . . . . . . . . . . . . . .112 

Flat roof installation . . . . . . . . . . . . . . . . .94, 134, 140 

Floorstanding boiler . . . . . . . . . . . . . . . . . . . . . . . . .58 

Flow rate 

Collector array . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102 

Connection in parallel . . . . . . . . . . . . . . . . . . . . . . . .104 

Connection in series . . . . . . . . . . . . . . . . . . . . . . . . .103 

Connection in series and in parallel . . . . . . . . . . . . . .105 

Frost protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 

Function module (solar) 

FM244 (Logamatic 2107) . . . . . . . . . . . . . . . .29–30, 46 

FM443 (Logamatic 4000, EMS) . . . 28–29, 31, 41–43, 46 

SM10 (Logamatic EMS) . . . . . . . . . . . . . . . . . .28–29, 46 

H 

Heat meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 

High-Flow operation . . . . . . . . . . . . . . . . . . . . . . . . .28 

Hydraulic connection accessories . . . . . . . . . . . . . .121 

Hydraulic connections 

Collector array (options) . . . . . . . . . . . . . . . . . . . . . . .98 

Connection in parallel . . . . . . . . . . . . . . . . . . . . .98, 100 

Connection in series . . . . . . . . . . . . . . . . . . . . . . .98–99 


HZG kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 

I 

Inlet pressure (DEV) . . . . . . . . . . . . . . . . . . . . . . . .111 

Insolation map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 

Installation instructions . . . . . . . . . . . . . . . . . . . . . .139 

Installation system (collector array) 

Flat roof installation . . . . . . . . . . . . . . . . . . . . . .134, 140 

Roof integration . . . . . . . . . . . . . . . . . . . . . . . . . . . .131 

Rooftop installation . . . . . . . . . . . . . . . . . .123–126, 129 

Wall installation . . . . . . . . . . . . . . . . . . . . . . . . .138–139 

Installation times (collectors) . . . . . . . . . . . . .139, 141 

Intrinsic safety of a solar heating system . . . . . . . .112 

L 

List of abbreviations . . . . . . . . . . . . . . . . . . . . . . . .147 

Logalux P750 S... combi cylinder 

See also thermosiphon combi cylinder... 

Design and function . . . . . . . . . . . . . . . . . . . . . . . . . .17 

Dimensions and specification . . . . . . . . . . . . . . . . . . .20 

Pressure drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109 

Sample system . . . . . . . . . . . . . . . . . . . . . . . . . . .67–69 

Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86 

Logalux PL... thermosiphon thermal store 


Appendix 7 



Pressure drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 

Sample system . . . . . . . . . . . . . . . . . . . . . 64–66, 70–75 

Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 

Logalux PL.../2S... Thermosiphon combi cylinder 

Pressure drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 

Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 

Logalux PL.../2S... thermosiphon combi cylinder 

Design and function . . . . . . . . . . . . . . . . . . . . . . . 18–19 


Sample system . . . . . . . . . . . . . . . . . . . . . . . . . . . 67–69 

Logalux SL... thermosiphon cylinder 

See dual-mode thermosiphon cylinder Logalux SL... 

Logalux SM... dual-mode cylinder 


Logasol KS... compact station 

Diaphragm expansion vessel, . . . . . . 111–112, 116–117 

Selection (pressure drop, flow rate) . . . . . . . . . . . . . 109 

Logasol KS... complete station 

Diaphragm expansion vessel . . . . . . . . . . . . . . . . . . . 47 

Diaphragm expansion vessel, . . . . . . . . . . . . . . . . . . . 46 


Equipment level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 

External control . . . . . . . . . . . . . . 28–29, 31, 41–43, 46 

Integral control unit . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 

Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 

Low-Flow operation . . . . . . . . . . . . . . . . . . . . . . . . . 28 

O 

On-site fixing 

Flat roof installation . . . . . . . . . . . . . . . . . . . . . . . . . 137 

Wall installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 

On-site safety 

Installation instructions . . . . . . . . . . . . . . . . . . . . . . . 139 

Optimisation function (solar) . . . . . . . . . . . . . . . . . . 29 

Overvoltage protection 

Control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 

P 

Pasteurisation control . . . . . . . . . . . . . . . . . . . . 87, 89 

Pipework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108, 118 

Pre-cooling vessel . . . . . . . . . . . . . . . . . . . . . . . . . . 117 


Logasol SAT-VWS system . . . . . . . . . . . . . . . . . . . 45, 90 

pre-heat cylinder 

Logasol SAT-VWS system . . . . . . . . . . . . . . . . . . . . . . 88 

Sample system . . . . . . . . . . . . . . . . . . . . . 62–63, 65–66 

Pressure drop 

Collector row . . . . . . . . . . . . . . . . . . . . . . . . . . 102, 106 

Connection in parallel . . . . . . . . . . . . . . . . . . . . . . . 104 

Connection in series . . . . . . . . . . . . . . . . . . . . . . . . . 103 

145

7 

Appendix 


Logasol KS... compact station . . . . . . . . . . . . . . . . . .109 

Pipework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108 

Solar cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109 

Primary energy saving . . . . . . . . . . . . . . . . . . . . . . .29 

Pump sizing (SWT) . . . . . . . . . . . . . . . . . . . . . . . . . .56 

Q 

Questionnaire for detached houses 

and two-family homes (fax) . . . . . . . . . . . . . .142–143 

R 

Reheating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3, 58 

Reheating optimisation . . . . . . . . . . . . . . . . . . . . . . .29 

Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59 

Roof integration . . . . . . . . . . . . . . . . . . . . . . . . .92–93 

Rooftop installation . . . . . . . . . . . 92–93, 123–126, 129 

RW return temperature limiter . . . . . . . . . . . . . . . . .55 

S 

Safety regulations . . . . . . . . . . . . . . . . . . . . . . . . . . .59 

Sizing 

Diaphragm expansion vessel, . . . . . . 111–112, 116–117 

Logasol KS... compact station (selection) . . . . . . . . . .109 

Solar heating system for detached house/ 

two-family home (DHW) . . . . . . . . . . . . . . . . .80, 82–83 

Solar heating system for detached house/ 

two-family home (DHW+HTG) . . . . . . . . . . . . . . .84, 86 

Solar heating system, apartment block 

with 3 to 5 residential units (DHW) . . . . . . . . . . . . . . .87 

Solar heating system, apartment block 

with up to 30 residential units (DHW) . . . . . . . . . .88–90 

Space required for flat roof installation . . . . . . . . . . . .94 

Space required for rooftop installation and roof 

integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93 

Space requirement with rooftop installation and roof 

integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92 

Space requirement, wall mounting . . . . . . . . . . . . . . .96 

Swimming pool water heating . . . . . . . . . . . . . . . . . .91 

Solar collector Logasol SKN3.0 

Design and function . . . . . . . . . . . . . . . . . . . . . . . . . . .4 

Dimensions and specification . . . . . . . . . . . . . . . . . . . .5 

Installation times . . . . . . . . . . . . . . . . . . . . . . . .139, 141 

Solar collector Logasol SKS4.0 


Dimensions and specification . . . . . . . . . . . . . . . . . . . .8 

Installation times . . . . . . . . . . . . . . . . . . . . . . . .139, 141 

Solar collector Vaciosol CPC... 


Dimensions and specification . . . . . . . . . . . . . . . . . . .11 

Solar control unit 

Solar control unit SC10 . . . . . . . . . . . . . . . . . . . . . . . .33 

Solar control unit SC20 . . . . . . . . . . . . . . . . . .34–35, 46 

Solar control unit SC40 . . . . . . . . . . . . . . . . . .35–40, 46 

146 

Solar function module FM244 . . . . . . . . . . . . 29–30, 46 

Solar function module FM443 . . . 28–29, 31, 41–43, 46 

Solar function module SM10 . . . . . . . . . . . . . 28–29, 46 

Selection aids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

Solar fluid L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50–51 

Solar heating system enquiry for detached houses 

and two-family homes (fax) . . . . . . . . . . . . . . 142–143 

Solar optimisation function . . . . . . . . . . . . . . . . . . . 29 

Solid fuel boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 

Sample system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 

Space requirement 

Flat roof installation . . . . . . . . . . . . . . . . . . . . . . . . . . 94 

Rooftop installation and roof integration . . . . . . . 92–93 

Wall mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 

Stagnation temperature . . . . . . . . . . . . . . . . . . 5, 8, 11 

Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 


Flat roof installation . . . . . . . . . . . . . . . . . . . . . . . . . 136 

Roof integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 

Rooftop installation . . . . . . . . . . . . . . . . . . . . . . . . . 128 

Wall installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 

Swimming pool water heat exchanger SWT . . . . . . 56 

Swimming pool water heating (sizing) . . . . . . . . . . 91 

System volume (solar part) . . . . . . . . . . . . . . . . . . 110 


T 

Technical rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 

Temperature differential control . . . . . . . . . . . . . . . 27 

Testing the solar fluid . . . . . . . . . . . . . . . . . . . . . . . 51 

Thermal insulation . . . . . . . . . . . . . . . . . . . . . . . . . 118 

Thermal store 

See Logalux PL... thermosiphon thermal store 

Thermostatic DHW mixer assembly . . . . . . . . . . 52–54 

Twin-Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 

Two consumers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 

Tyfocor LS (solar fluid) . . . . . . . . . . . . . . . . . . . . . . . 51 

V 

Vaciosol CPC... 

See Vaciosol CPC... solar collector 

Vapour safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 

Volume of a solar heating system . . . . . . . . . . . . . 110 

W 

Wall installation . . . . . . . . . . . . . . . . . . . . . . . 138–139 

Wall mounted boiler . . . . . . . . . . . . . . . . . . . . . . . . 58 

Detailed hydraulic scheme . . . . . . . . . . . . . . . . . . . . . 78 

Sample system . . . . . . . . . . . . 61, 63–65, 68–69, 71, 74 

Wall mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96


Rooftop installation . . . . . . . . . . . . . . . . . . . . . . . . . .128 


Appendix 7 

147

7 

Appendix 

List of abbreviations 

Abb. Description 

AK Cold water outlet (buffer system) 

AV Shut-off valve 

AW/AB DHW outlet 

E Air vent valve 

EH Immersion heater 


EL Drain 

EW DHW inlet (primary system) 


FA Outside temperature sensor 

FE Fill & drain valve 

FK Boiler water temperature sensor 

FR Return temperature sensor 


FP Thermal store temperature sensor 

FPO Thermal store temperature sensor, top 

FPU Thermal store temperature sensor, bottom 

FSB Swimming pool water temperature sensor 

FSS1 Cylinder temperature sensor (1st consumer) 

FSS2 Cylinder temperature sensor (2nd consumer) 

FSW1 Heat meter temperature sensor Flow 

FSW2 Heat meter temperature sensor return 

FSX 

FSX1 

FSX2 

FSX3 

148 

Cylinder temperature sensor or threshold sensor for 

thermosiphon cylinder for High-Flow-/Low-Flow 

operation with solar function module FM443 or 

SM10 

(Cylinder connection set AS1, AS16 or DHW 

temperature sensor FB or FW) 

FV Flow temperature sensor 

HK Heating circuit 

HS (-E) 

Heating circuit quick assembly set, optionally with 

self-regulating electronic pump 

HSM (-E) 

HS with actuator (mixer), optionally with selfregulating 

electronic pump 

HZG HZG set for central heating backup 

Abb. Description 

Measuring point (e.g. cylinder), motor (e.g. 

M 

actuator) 

MB Domestic hot water measuring point 

MAG Diaphragm expansion vessel 

PH Heating circuit pump 

PS Cylinder primary pump 

PSB Swimming pool water pump 


PUM Stratification pump 

PWT Heat exchanger pump 

PZ DHW circulation pump 

R Return; solar return 

RK Boiler return 

RS Cylinder return 

RSB Swimming pool control unit 

RW Return temperature limiter 

SA Line regulating and shut-off valve 

SH Heating circuit actuator 

SMF Dirt filter 

SP1 Overvoltage protection 

SU Diverter valve 

SV Safety valve 

SWT Swimming pool water heat exchanger 

TW Drinking water/DHW 

TWE Domestic hot water heating 

ÜV Overflow valve 

V Flow; solar flow 

VK Boiler flow 

VS Cylinder flow 

VS-SU Diverter valve to 2nd consumer VS-SU 

Heat 

source 

Residential unit 

WT Heat exchanger 

WMZ 

Heat meter set WMZ1.2 in conjunction with solar 

function module FM443 

WWM Thermostatically controlled DHW mixer 



Appendix 7 

149

7 Appendix 

150 



Appendix 7 

151

7 Appendix 

152 


High grade heating technology requires professional installation and maintenance. Buderus, therefore, supplies its 

complete range only through approved heating engineers. Ask your local heating contractor for Buderus heating 

technology, inform yourself at one of our sales offices or visit our website. 

Branch Post Code/Town Street Telephone Fax Responsible 

service centre 

1. Aachen 52080 Aachen Hergelsbendenstr. 30 (0241) 9 68 24-0 (0241) 9 68 24-99 Trier 

2. Augsburg 86156 Augsburg Werner-Heisenberg-Str. 1 (0821) 4 44 81-0 (0821) 4 44 81-50 München 

3. Berlin-Tempelhof 12103 Berlin-Tempelhof Bessemerstr. 76 a (030) 7 54 88-0 (030) 7 54 88-1 60 Berlin 

4. Berlin/Brandenburg 16727 Velten Berliner Str. 1 (03304) 3 77-0 (03304) 3 77-1 99 Berlin 

5. Bielefeld 33719 Bielefeld Oldermanns Hof 4 (0521) 20 94-0 (0521) 20 94-2 28/2 26 Hannover 

6. Bremen 28816 Stuhr Lise-Meitner-Str. 1 (0421) 89 91-0 (0421) 89 91-2 35/2 70 Hamburg 

7. Dortmund 44319 Dortmund Zeche-Norm-Str. 28 (0231) 92 72-0 (0231) 92 72-2 80 Dortmund 

8. Dresden 01458 Ottendorf-Okrilla Jakobsdorfer Str. 4-6 (035205) 55-0 (035205) 55-1 11/2 22 Leipzig 

9. Düsseldorf 40231 Düsseldorf Höher Weg 268 (0211) 7 38 37-0 (0211) 7 38 37-21 Dortmund 

10. Erfurt 99091 Erfurt Alte Mittelhäuser Straße 21 (0361) 7 79 50-0 (0361) 73 54 45 Leipzig 

11. Dining 45307 Essen Eckenbergstr. 8 (0201) 5 61-0 (0201) 56 1-2 79 Dortmund 

12. Esslingen 73730 Esslingen Wolf-Hirth-Str. 8 (0711) 93 14-5 (0711) 93 14-6 69/6 49/6 29 Esslingen 

13. Frankfurt 63110 Rodgau Hermann-Staudinger-Str. 2 (06106) 8 43-0 (06106) 8 43-2 03/2 63 Gießen 

14. Freiburg 79108 Freiburg Stübeweg 47 (0761) 5 10 05-0 (0761) 5 10 05-45/47 Esslingen 

15. Gießen 35394 Gießen Rödgener Str. 47 (0641) 4 04-0 (0641) 4 04-2 21/2 22 Gießen 

16. Goslar 38644 Goslar Magdeburger Kamp 7 (05321) 5 50-0 (05321) 5 50-1 14/1 39 Hannover 

17. Hamburg 21035 Hamburg Wilhelm-Iwan-Ring 15 (040) 7 34 17-0 (040) 7 34 17-2 67/2 31/2 62 Hamburg 

18. Hannover 30916 Isernhagen Stahlstr. 1 (0511) 77 03-0 (0511) 77 03-2 42/2 59 Hannover 

19. Heilbronn 74078 Heilbronn Pfaffenstr. 55 (07131) 91 92-0 (07131) 91 92-2 11 Esslingen 

20. Ingolstadt 85098 Großmehring Max-Planck-Str. 1 (08456) 9 14-0 (08456) 9 14-2 22 München 

21. Kaiserslautern 67663 Kaiserslautern Opelkreisel 24 (0631) 35 47-0 (0631) 35 47-1 07 Trier 

22. Karlsruhe 76185 Karlsruhe Hardeckstr. 1 (0721) 9 50 85-0 (0721) 9 50 85-33 Esslingen 

23. Kempten 87437 Kempten Heisinger Str. 21 (0831) 5 75 26-0 (0831) 5 75 26-50 München 

24. Kiel 24145 Kiel-Wellsee Edisonstr. 29 (0431) 6 96 95-0 (0431) 6 96 95-95 Hamburg 

25. Koblenz 56220 Bassenheim Am Gülser Weg 15-17 (02625) 9 31-0 (02625) 9 31-2 24 Gießen 

26. Köln 50858 Köln Toyota-Allee 97 (02234) 92 01-0 (02234) 92 01-2 37 Dortmund 

27. Kulmbach 95326 Kulmbach Aufeld 2 (09221) 9 43-0 (09221) 9 43-2 92 Nürnberg 

28. Leipzig 04420 Markranstädt Handelsstr. 22 (0341) 9 45 13-00 (0341) 9 42 00 62/89 Leipzig 

29. Magdeburg 39116 Magdeburg Sudenburger Wuhne 63 (0391) 60 86-0 (0391) 60 86-2 15 Berlin 

30. Mainz 55129 Mainz Carl-Zeiss-Str. 16 (06131) 92 25-0 (06131) 92 25-92 Trier 

31. Meschede 59872 Meschede Zum Rohland 1 (0291) 54 91-0 (0291) 66 98 Gießen 

32. München 81379 München Boschetsrieder Str. 80 (089) 7 80 01-0 (089) 7 80 01-2 58/2 71 München 

33. Münster 48159 Münster Haus Uhlenkotten 10 (0251) 7 80 06-0 (0251) 7 80 06-2 21/2 31 Dortmund 

34. Neubrandenburg 17034 Neubrandenburg Feldmark 9 (0395) 45 34-0 (0395) 4 22 87 32 Berlin 

35. Neu-Ulm 89231 Neu-Ulm Böttgerstr. 6 (0731) 7 07 90-0 (0731) 7 07 90-92 München 

36. Norderstedt 22848 Norderstedt Gutenbergring 53 (040) 50 09 14 17 (040) 50 09 - 14 80 Hamburg 

37. Nürnberg 90425 Nürnberg Kilianstr. 112 (0911) 36 02-0 (0911) 36 02-2 74 Nürnberg 

38. Osnabrück 49078 Osnabrück Am Schürholz 4 (0541) 94 61-0 (0541) 94 61-2 22 Hannover 

39. Ravensburg 88069 Tettnang Dr. Klein-Str. 17-21 (07542) 5 50-0 (07542) 5 50-2 22 Esslingen 

40. Regensburg 93092 Barbing Carl-Zeiss-Str. 16 (09401) 8 88-0 (09401) 8 88-92 Nürnberg 

41. Rostock 18182 Bentwisch Hansestr. 5 (0381) 6 09 69-0 (0381) 6 86 51 70 Berlin 

42. Saarbrücken 66130 Saarbrücken Kurt-Schumacher-Str. 38 (0681) 8 83 38-0 (0681) 8 83 38-33 Trier 

43. Schwerin 19075 Pampow Fährweg 10 (03865) 78 03-0 (03865) 32 62 Hamburg 

44. Traunstein 83278 Traunstein/Haslach Falkensteinstr. 6 (0861) 20 91-0 (0861) 20 91-2 22 München 

45. Trier 54343 Föhren Europa-Allee 24 (06502) 9 34-0 (06502) 9 34-2 22 Trier 

46. Viernheim 68519 Viernheim Erich-Kästner-Allee 1 (06204) 91 90-0 (06204) 91 90-2 21 Trier 

47. Villingen-Schwenningen 78652 Deißlingen Baarstr. 23 (07420) 9 22-0 (07420) 9 22-2 22 Esslingen 

48. Wesel 46485 Wesel Am Schornacker 119 (0281) 9 52 51-0 (0281) 9 52 51-20 Dortmund 

49. Würzburg 97228 Rottendorf Edekastr. 8 (09302) 9 04-0 (09302) 9 04-1 11 Nürnberg 

50. Zwickau 08058 Zwickau Berthelsdorfer Str. 12 (0375) 44 10-0 (0375) 47 59 96 Leipzig 

Service-Center Telephone Fax 

Berlin: (0180) 3 22 34 00 (030) 75 48 82 02 

Dortmund: (0180) 3 67 14 04 (0231) 9 27 22 88 

Berlin: (0180) 3 22 34 00 (030) 75 48 82 02 

Esslingen: (0180) 3 67 14 02 (0711) 9 31 47 16 

Gießen: (0180) 3 22 34 34 (06441) 4 18 27 97 

Hamburg: (0180) 3 67 14 00 (040) 73 41 73 20 

Hannover: (0180) 3 67 14 01 (0511) 7 70 31 03 

Leipzig: (0180) 3 67 14 06 (0341) 9 45 14 22 

München: (0180) 3 22 34 01 (089) 78 00 14 30 

Nürnberg: (0180) 3 67 14 03 (0911) 3 60 22 31 

Trier: (0180) 3 67 14 05 (06502) 93 44 20 

BBT Thermotechnik GmbH 

Buderus Deutschland 

35573 Wetzlar 

www.buderus.de 

info@buderus.de 

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7 747 011 220 (20) Brühl 07/2007 Printed in Germany. 

Subject to technical modifications.

Technical guide Heat is our element - Buderus

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