Installation and Operating Instruction

Installation and 

Operating Instruction 

Gebr. Bruns GmbH 

Hauptstraße 200 

D 26683 Saterland 

Tel.: + 49 (0) 44 92 / 92 46 0 

Fax: + 49 (0) 44 92 / 71 41 

BOY III 

Condensing Gas Boiler 

Stand 11/2009

Table of contents 

1 Introduction 4 

1.1 Symbols used in this manual 4 

1.2 Liability 4 

1.3 Factory Warranty 4 

2 Product Description 5 

2.1 Product Description 5 

2.2 Intended use 5 

2.3 Equipment configuration BOY III Solo 6 

2.4 Equipment configuration BOY III Combi 7 

3 Regulations, Guidelines, Safety 8 

3.1 Regulations and Guidelines 8 

3.2 Safety Warning 9 

3.2.1 What to Do if You Smell Gas 9 

3.2.2 Risk of Poisoning 9 

3.2.3 Risk of Freezing 10 

3.2.4 Relief Valve 10 

3.2.5 Aspirator 10 

3.2.6 Pressure Compensating Tank for Drinking Water 11 

3.2.7 Pressure Compensating Tank for the Heating System 11 

3.2.8 Water Deficiency Safety Fuse 11 

3.2.9 High Temperature cut out 11 

3.2.10 Corrosion Protection 12 

3.2.11 Installation Location Requirements 12 

3.2.12 Minimum Safety Distances 12 

4 Mounting/Installation 13 

4.1 Shipment Contents 13 

4.2 Mounting the Unit 14 

4.2.1 General Instructions for Connection the Heating Unit 15 

4.2.2 Connecting the Heating Unit (Supply and Return Lines) 15 

4.2.3 Connecting for Drinking Water (BOY III Combi) 16 

4.2.4 Connecting for Use with an External Reservoir 16 

4.2.5 General Instructions for the Gas Connection 17 

4.2.6 Connecting the Gas Main 17 

4.2.7 General Instructions for Connecting the Gas Flue 18 

4.2.8 Chimney Compatibility 18 

4.2.9 Heating Duct Requirements 18 

4.2.10 Maximum Length of Flue Ducts and Number of Directional Changes 18 

4.2.11 Reducing the Maximum Delivery Height 18 

4.2.12 Lighting Protection 18 

4.2.13 Connecting the Unit to the Chimney 19 

4.2.14 Installing the Emissions Connection to Central Roof Heating 21 

4.2.15 Connecting the Condensed Water Drain 21 

4.2.16 Neutralisation 21 

4.2.17 General Instructions for the Electrical Connection 22 

4.2.18 Electrical Connection 22 

4.2.19 Pin Assignment on the Terminal Strip 23 

Gebr. Bruns GmbH is not responsible for typographical errors or technical inaccuracies and reserves the right to make adjustments. 

Gebr. Bruns GmbH • Hauptstraße 200 • 26683 Saterland •Tel.: + 49 (0) 44 92 / 92 46-0 • Fax: + 49 (0) 44 92 / 71 41 

www.bruns-heiztechnik.de • info@bruns-heiztechnik.de

Table of contents 

5 Start up 24 

5.1 Filling and Ventilating the Heating System 24 

5.2 Ventilating the Unit 24 

5.3 Ventilating the Lower/Standing Reservoir (optional) 25 

5.4 Start up 26 

5.4.1 Performance of the Unit Test Routine upon Start up 26 

5.5 (Pre) Setting the Boiler 26 

5.5.1 CO2 Boiler Settings 26 

5.5.2 Gas Throughput Table / Connection Pressure 27 

5.5.3 Changing Gas Types 27 

6 Operating the Controls 28 

6.1 Description of the Control Panel 28 

6.2 LED Display Symbols 28 

6.3 Controller Functions and Operating Status 29 

6.3.1 Start up 29 

6.3.2 Standby Mode 29 

6.3.3 Flame Detector 29 

6.3.4 Central Heating Mode 30 

6.3.4.1 Operating the Central Heater 30 

6.3.4.2 Anti-Cycling Central Heating 30 

6.3.5 Drinking Water Mode 30 

6.3.5.1 Operating the Drinking-Water Heater 30 

6.3.5.2 Anti-Cycling Drinking-Water Heater 31 

6.3.6 Changing the Set-point 31 

6.3.6.1 Changing the Set-point for Central Heating 31 

6.3.6.2 Changing the Set-point for the Drinking-Water Heater 31 

6.3.7 Summer Mode 32 

6.3.8 Chimney Sweep Mode 32 

6.3.9 Installer Mode 32 

6.3.10 Installer (+) Mode 33 

6.3.10.1 Installer (+) Parameter List 34 

7 Malfunctions and Errors 36 

7.1 Error Mode 36 

7.2 Error Code List 36 

7.2.1 Shutdown Codes 36 

7.2.2 Locking Codes 37 

7.3 Error history Mode 39 

7.4 Log Resistance Values for the Boiler and Reservoir Sensors 39 

8 Maintenance 40 

8.1 General Instructions for Maintenance 40 

8.2 Cleaning the Condensed Water Siphon 40 

8.3 Cleaning the Combustion Chamber 40 

9 Technical Data 43 

9.1 Circuit Diagram 43 

9.2 Technical Data 44 

10 Declaration of Conformity 46 




Introduction 

1 Introduction 

Dear customer, 

We congratulate you on your decision to use the BOY III Condensing Gas Boiler. By 

purchasing the BOY III, you have secured the most current level of innovation in boiler 

technology. 

We will gladly answer any questions or provide any information you may need. 

We thank you for your trust and hope you enjoy you BOY III Condensing Gas Boiler. 

Gebr. BRUNS GmbH, 

Your partner for heating technology 

1.1 Symbols used in this manual 

Failure to follow instructions marked with this symbol risks life and limb; a defect 

in the unit is possible. 

This Symbol denotes important Instructions and Information. 

This symbol marks tasks to be fulfilled. 

1.2 Liability 

Gebr. Bruns GmbH is not liable for damages caused by not observing this installation 

and operating instruction. 

1.3 Factory Warranty 

We provide a factory warranty for the owner in accordance with the current conditions 

and deadlines in the Gebr. Bruns GmbH’s general terms and conditions. The 

warranty does not cover damages caused by normal wear and tear, insufficient water 

quality, aggressive fumes or strong dust. Warranty work is performed exclusively by 

the factory. We can, therefore, only reimburse you for expenses incurred for repairs 

done during the warranty period if we have received a proper order and have 

deemed it to be covered by the warranty. 

- 4 - 




Product Description 

2 Product Description 

2.1 Product Description 

The BOY III is a compact, wall-hanging condensing gas boiler that weighs very little. 

The BOY III can be operated dependent or independent of compartment air. All of 

the basic parts are inside the powder-coated steel-plated casing. The stainless steel 

heat exchanger is designed for exhaust condensation operation and is very selfcleaning. 

With its 1:5 modulation ratio, the force draught fan supported burner, designed 

especially for gas boilers, is very efficient in its energy use and emissions. 

The connections can be placed from below the unit. An atmospheric or temperature 

sensor can be attached to the boiler controller. These sensors can, depending on 

how they are set up, regulate up to two mixing valve circuit. 

2.2 Intended use 

Fig. 1: Boy III 

The BOY III is a condensing gas boiler and is exclusively for use as a heating 

unit for heating systems. 

Any misuse is prohibited 

- 5 - 





2.3 Equipment configuration BOY III Solo 

Burner Unit 

Ionisation 

Force Draught Fan 

Relief Valve 

Flow Sensor 

Water Pressure Sensor 

Fig. 2: BOY III Solo 

- 6 - 

High Temperature 

Sensor 

Ignition Electrode 

Automatic Firing Device 


Gas Valve 

Return Sensor 

Circulation Pump 




2.4 Equipment configuration BOY III Combi 

Burner Unit High Temperature 

cut out 

Ionisation 

Force Draught Fan 

Plate Heat 

Exchanger 

Relief Valve 

Flow Sensor 

Water Pressure Sensor 

Fig. 3: BOY III Combi 

Warm Water Sensor Circulation Sensor 

- 7 - 

Ignition Electrode 

Automatic Firing Device 


Gas Valve 

Return Sensor 

Circulation Pump 



Regulations, Guidelines, Safety 

3 Regulations, Guidelines, Safety 

3.1 Regulations and Guidelines 

Regarding mounting, installation, and operation of the BOY III, the following laws, ordinances, 

regulations, norms and rules apply according to the current versions. 

In other countries, the respective national regulations apply. 

BImSchV Federal Emissions Protection Regulation 

DIN 18160 Emissions Systems – Design and Operation 

DIN 18380 Heating Systems and Central Water Heating Systems 

DIN 1988 Teil 1 – 8 Technical Regulations for Drinking Water Installation 

DIN 4753 Water heater and Water heating Systems for Drinking Water 

and Domestic Use 

DIN EN 12828 Water heating System Design 

DIN EN 12831 Procedure for Calculating the Heating Load Norm 

DIN EN 13384 Procedure for Calculating Emissions Systems – Heat and 

Supply 

DIN EN 267 Automatic Burner with Force Draught Fan for Liquid Fuels 

DVGW G 631 Installation of Commercial Gas Consuming Appliances 

DVGW G 634 Installation of Gas Units in Commercial Kitchens in Buildings 

DVGW G 670 Gas Fire Locations and Mechanical Ventilation Systems 

DVGW TRGI 86 Technical Regulations for Gas Installation 

EnEG Energy Conservation Law 

EnEV Energy Conservation Regulation 

FeuVO Fire Regulations per State 

VDE Rules and Regulations for Electro-Technical, Electronics, 

and Information Technology 

VDI 2035 Prevention of Damages in Water Heating Systems – Accumulation 

of Stone in Drinking Water and Water Heating systems 

– Corrosive Water – Corrosive Emissions 

This list may not be complete! 

Before installing the condensing gas boiler BOY III, it is necessary to attain 

approval from the Gas Supply Ordinance Board and the District Chimney 

Sweep Foreman. 

- 8 - 





3.2 Safety Warning 

Attention: Electrical installation and initial operation may only be performed by 

a licensed professional! This also pertains to maintenance, cleaning, and repair. 

● Do not use if system is damaged. 

● Only original parts may be used. 

● Changes and repairs made on one’s own authority are not allowed, as 

such may result in damages to the unit or injury or death. 

● When operated in a compartment air-dependent area, ventilation (in 

and out) must not be obstructed. The intake of combustion air on the 

top of the BOY III must be kept free of obstructions. 

3.2.1 What to Do if You Smell Gas 

Avoid open fire, smoking, turning on lights, or unplugging anything in rooms 

that smell like gas. Under no circumstances should you use the telephone. 

Close the gas meter valve! Have your installation technician show you where 

the gas valve is and how to close it. 

Do not use doorbells or light switches in other rooms. 

If you smell gas, use a telephone in a neighbouring building or use a phone 

booth. Mobile phones should also be used outside of the building. 

Call the service department, even if you smell gas somewhere else. 

Do not forget to warn housemates and neighbours and vacate the premises. 

Secure the building against unauthorized entry. 

Even if you aren’t sure if it is a gas smell, you should contact your energy provider 

as a precaution. 

3.2.2 Risk of Poisoning 

Never use water from the heating system as drinking water! It is contaminated with 

deposits. 

- 9 - 





3.2.3 Risk of Freezing 

If the unit is at risk of freezing, it is necessary to be kept operational in conservation 

mode (at minimum) and all radiator valves should be kept open. If you cannot heat 

during freezing periods, turn off the system and empty the boiler, the warm water 

storage tank and the radiators. The boiler must be secured against accidental activation 

when empty. 

3.2.4 Relief Valve 

The condensing gas boiler comes with a 2.5 bar relief 

valve. The opening of the spring-loaded membranous 

relief valve must be in a frost free area and must be easily 

accessible. The blow off pipe on the relief valve must 

be implemented without the possibility of increasing 

pressure while responding to the relief valve. Leaking 

heater water should be safely siphoned off. 

Operational readiness of the relief valve should be 

checked from time to time. 

3.2.5 Aspirator 

To ventilate the boiler with water in it, the 

aspirator cap on the top of the unit must be 

open by turning it two rotations to the left. 

An additional automatic aspirator can be 

found under the pump casing. This may 

only be set by a licensed professional. 

- 10 - 

Fig. 4 Relief Valve 

Fig. 5 Manual Quick-Aspirator 

Fig. 6 Automatic Quick-Aspirator 





3.2.6 Pressure Compensating Tank for Drinking Water 

In combination with a drinking water reservoir, 

a membranous pressure compensating 

tank that has been approved for filtering 

domestic-use water to drinking water is required. 

This tank should have ample space 

and must be installed externally in accordance 

with TRWI regulations. The size of the 

tank is dependent upon the volume of domestic-use 

water reservoir. 

3.2.7 Pressure Compensating Tank for the Heating System 

On the heater side, a membranous pressure 

compensating tank is required. This 

tank should have ample space and is to be 

installed externally. The size of the tank is 

dependent upon the volume of heating system’s 

water reservoir as well as the temperature 

requirements. 

Fig. 7 Pressure Compensating Tank for 

Drinking Water 

Fig. 8 Pressure Compensating Tank for the 

Heating System 

Setting the primary pressure of the pressure compensating tanks to the 

respective static levels is required and may only be performed by a licensed 

professional. 

3.2.8 Water Deficiency Safety Fuse 

A minimum circulation rate of 360 l/h is required. Furthermore, a water pressure 

sensor makes sure that at a system pressure of 0.6 bar, the system automatically 

shuts down. As soon as the water pressure returns to above 0.6 bar, the unit 

will turn itself back on automatically. 

3.2.9 High Temperature cut out 

The unit has a temperatur cut out with a melting fuse. This safety guard is only a protection 

against burning out of the heat exchanger. If this fuse is blown out, the complete 

heat exchanger has to be changed, because the baffle plate within, is most 

probably damaged. 

- 11 - 





3.2.10 Corrosion Protection 

The combustion air must be free of all corrosive elements – especially those containing 

fluoride and chloride such as those found in solvents and cleaning solutions, propellants 

an so on. 

When connecting a water heater to a floor heater with non-airtight plastic tubing (in 

accordance with DIN 4726), a heat exchanger must be used to separate the systems. 

To avoid corrosion damage in the heating system, heating water that fulfils the drinking 

water quality requirements in VDI guideline 2035 (Prevention of Damages in Water 

Heating Systems) must be used. Chemical additives are not to be used. 

3.2.11 Installation Location Requirements 

● When operated in a compartment air-dependent area, the unit must be housed 

in a room with clean combustion air. Under no circumstances should foreign 

substances such as pollen get inside the unit via the intake duct! 

● The installation location must be dry and frost free (0°C to 45°C). 

● The boiler room must be protected against small animals, vermin and pests. 

● When operated in a compartment air-dependent area, the boiler room must 

have a functioning ventilation and emission system. 

● Flammable material or liquids must not be stored or used near the boiler. Follow 

fire prevention guidelines! 

3.2.12 Minimum Safety Distances 

For optimal installation of the boiler, 

we recommend a lateral distance of 

200 mm from the walls and a vertical 

distance of 500 mm from the ceiling. 

Reducing these distances is allowed 

according to legal guidelines. 

The lateral distances should not fall 

below 100 mm. 

- 12 - 

200 

4 0 0 

Fig. 9 Minimum Safety Distances (mm) 




Mounting / Installation 

4 Mounting/Installation 

4.1 Shipment Contents 

Please make sure the shipment is complete and undamaged before you begin 

with the installation! 

The delivery comes in a cardboard box. 

1 

Fig. 10 Shipment Contents 

Pos. Anzahl Bezeichnung 

1 1 Condensing Gas Boiler BOY III 

2 1 Atmospheric or Temperature Sensor (Optional) 

3 1 Pressure Gauge 

4 1 Control Keypad with Illuminated Display 

5 1 Wall Mounting Track 

6 2 Mounting Screws incl. Washers 

7 2 Plastic Expansion Studs 

8 1 Installation and Operation Manual 

- 13 - 



www.bruns-heiztechnik.de • info@bruns-heiztechnik.de 

2 

3 

4 

5 

6 

7


4.2 Mounting the Unit 

The unit comes with a track for easy wall mounting. Before mounting the 

unit, please read the following requirements: 

• The wall must be stable enough to hold the unit. 

• An outlet with contact protection for electricity and a water drainage 

connection should both be in close proximity. 

• Make sure to check the wall for electrical wiring and water and gas pipes 

before drilling as they may get damaged. 

• To protect the boiler from contamination, place protective covers over 

all connections. Please remove these only at the appropriate installation 

stage. 

Next, measure the wall intended as the location 

of the unit. Follow the measurements of 

the unit and the minimum safety distances. If 

the unit is to be attached to an existing chimney, 

use the emissions connection, including 

the elbow as the point of reference. 

Mark the drilling positions for the mounting 

track and drill using an 8 mm bit. 

Place the plastic expansion studs in the wall 

and fasten the track to the wall with the 

screws. Use a level to make sure the track is 

straight and then screw it tightly to the wall. 

Hang the unit to the mounted track and make 

sure it is mounted firmly. 

Use the setting screws at the bottom of the 

back of the boiler to align it parallel to the wall. 

Check one more time with the level to make 

sure the boiler is straight. 

- 14 - 

3 2 0 

Fig. 11 Wall Track 

8 5 

Fig. 12 Wall Mount (mm) 





4.2.1 General Instructions for Connection the Heating Unit 

● Before connecting the boiler to the heating system, the heating system 

must be rinsed at a minimum of 3 times the flow capacity. The drinking 

water pipes must be rinsed at a minimum of 20 times its flow capacity. 

● In older systems, a filter must be placed in the heating circuit in the return 

supply line before the opening to the boiler. 

● Use only untreated tap water to fill and refill the heating system. 

● The pH value must be between 6 and 9. 

● Do not add any chemicals to the heating system’s water (e.g. anti-freeze, 

water softener, solutions to raise or lower the pH value, chemical 

additives and/or inhibitors). These can damage the boiler. 

● When using plastic pipes (e.g. in floor heaters), the pipes must be air 

and diffusion tight in accordance with DIN 4726/ 4729. 

● If the system’s plastic pipes are not in accordance with the norms, we 

recommend separating the boiler circulation system from the heating 

system with a (plate) heat exchanger or a filter mounted hydraulically 

in front of the boiler connection. 

● The temperature of the heating ducts and radiators can go up to 95 °C. 

4.2.2 Connecting the Heating Unit (Supply and Return Lines) 

There are flue cut-off devices that must be 

mounted directly under the boiler. These 

should have the respective diameters of the 

connections to which they belong. Permanently 

soldered or welded connections are not 

allowed. 

A separate line for filling and draining must be 

installed and easily accessible. If the line for 

filling and draining is not at the lowest point of 

the unit, an additional device must be installed 

so the system can be completely drained. 

Older systems and floor heating systems require 

a filter in the return line directly on the 

boiler. 

S R A K 

V L S V 

R L 

G 

Fig. 13 Connections: BOY III Solo 

S R A K 

V L W W S V 

K W R L 

G 

Fig. 14 Connections: BOY III Combi 

SR Siphon-Cleaning VL Supply WW Warm Water SV Drainage Safety Valve 

AK Condensation Drainage RL Return Flow KW Cold Water G Gas Connection 

- 15 - 





4.2.3 Connecting for Drinking Water (BOY III Combi) 

The drinking water access must be 

equipped in accordance with DIN 1988 

and DIN 4753 to avoid dirt or germs that 

can contaminate the cold water network. 

The necessary parts and their configuration 

are shown in the diagram to the right. 

T W 

4.2.4 Connecting for Use with an External Reservoir 

1 2 3 4 5 6 

1 . C u t - o f f v a l v e 

2 . F i l t e r 

3 . P r e s s u r e r e g u l a t o r 

4 . C h e c k v a l v e 

5 . N o n e - r e t u r n e v a l v e 

6 . M a n o m e t e r c o n n e c t i o n 

T W . M a i n s d r i n k i n g w a t e r 

Fig. 15 Connection Schematic: 

Drinking Water Access 

If the unit is connected to an external reservoir, an expansion tank and a 10 bar relief 

valve must be installed to protect the heating system. The BOY III Solo requires an 

additional three-way redirecting valve installed in the return flow line directly on the 

boiler. 

Fig. 16 Three-way Redirecting Valve 

The connections on the three-way redirection 

valve are as follows: 

AB = Return Flow Line BOY III 

A = Reservoir Connection 

B = Heating Circuit Connection 

- 16 - 

These connections should never, under 

any circumstances, be interchanged! 

The three-way redirecting valve is 

already integrated in to the BOY III. 




1


4.2.5 General Instructions for the Gas Connection 

• The gas connection must be connected in accordance with the current 

regulations. Installation may only be performed by a licensed professional! 

• Make sure there is no open fire, flammable materials or the like in close 

proximity to the installation location. LIFE THREATENING DANGER! 

• Before installation, check to make sure the gas meter has adequate 

capacity. Take the usage of all household appliances into account. 

Let your energy provider know if your line does not have a high 

enough capacity. 

• Make sure the gas lines are clean. Clean the gas lines with high pressure 

or by knocking them clean before installation. 

• An approved shut-off valve with a fire protective faucet must be installed 

in front of the boiler. 

• Preferably, you can also install a gas filter to keep the gas control 

valve from getting dirty. 

4.2.6 Connecting the Gas Main 

Please follow these instructions during installation: 

• The main gas spigot must be shut off before the work begins. If the 

connection is older, make sure the spigot still closes to avoid uncontrolled 

gas leaking out. 

• Secure the line against accidental start up while you are working on 

the lines. 

• Make sure the fire protective faucet is mounted properly. 

• Before start up, make sure the entire gas line is sealed, especially at 

connection points. The gas faucet and the gas line may not exceed a 

maximum pressure of 150 mbar. 

• Ventilate the gas line after attaching to avoid malfunctions! 

• Ventilate the room well after installation to disperse any gas that may 

have escaped. 

- 17 - 





4.2.7 General Instructions for Connecting the Gas Flue 

Discuss regional guidelines for gas flue lines, cleaning openings and similar 

with the appropriate chimney sweep. 

4.2.8 Chimney Compatibility 

Heavily used and dirty chimneys are unsuitable for conducting combustion air (air 

supply through the chimney) and must be cleaned by a chimney sweep before use. 

If there are structural damages, such as brittle chimneys, soot build-up or the like, the 

chimney should be checked by a chimney sweep foreman to determine its stability. If 

cleaning the chimney isn’t possible, the unit can also be run through a concentric 

emissions pipe without being dependent upon compartment air. A compartment airdependent 

operating method is a possible alternative. 

Hooking up more than one or different types of boilers to one chimney should be approved 

by a chimney sweep foreman. 

4.2.9 Heating Duct Requirements 

Emission lines within buildings must be housed within their own ventilated ducts. 

The ducts must be made of non-flammable, form-holding materials. The duct’s fire 

resistance duration must be 90 minutes, in lower buildings, 30 minutes. 

4.2.10 Maximum Length of Flue Ducts and Number of Directional Changes 

Maximum length of 

Flue Duct 

Maximum Number of 

Directional Changes 

4.2.11 Reducing the Maximum Delivery Height 

Compartment air-dependent /Compartment air-independent 

Duct Layout Central Roof Heating 

21 m 4 m 

2 4 

When lengthening the connection lines by 1 m, the headroom of the emission lines is 

lowered by 1.5 m. Since the central roof heating system is limited to a total of 4.0 m, 

up to 4 directional changes can be installed. At an angle of 45°, the headroom is 

lowered by 0.5 m, at a 90° angle, by 1 m. 

4.2.12 Lighting Protection 

The chimney head cover must be into an existing lightning protection system and into 

a potential equalisation on the house. This should only be done by a licensed professional. 

- 18 - 





4.2.13 Connecting the Unit to the Chimney 

Calculate the height of the opening for 

the emission pipe. Make sure to take 

headroom for the test connection and the 

revision T-piece (T-fitting) into account. 

m a x . 1 6 0 m m 

Ø 1 0 m m 

Fig. 18 Cross Section of the Duct 

Position the support bar according to the 

diagram to the right. The support bar 

must be level. 

- 19 - 

2 1 0 m m 

Fig. 17 BOY III with Emission Connection 

The opening for mounting the support bar 

should be made according to the diagram. 

Make sure the opening is no larger 

than160 mm x 160 mm; otherwise 

the cover will not be large enough. 

Drill the hole for the support bar with a 10 

mm bit. The support bar must be level. 

Fig. 19 Installing the Support Bar 





Fig. 20 Insert the Emission Pipe into the Duct 

Mount the emission pipe between the unit 

and the support bar. The emission line to 

the unit must be placed at a slight downward 

slope, so condensation can flow 

back unhindered. 

Insert the pipe into the duct with a rope 

from above. The rope should stay taught 

at all times. Spacers should be placed 

every two meters after the collars. 

Place the support arc into the support 

bar. 

Fig. 21 Emission Connection - BOY III 

Follow the installation instructions for the respective emissions system! 

- 20 - 





4.2.14 Installing the Emissions Connection to Central Roof Heating 

Measure the point where the emission 

pipe opening will be based on the position 

of the unit. Install the special feed 

through socket as appropriate for the 

space provided. Lead the emission pipe 

through the socket and connect it to the 

unit. Use the sleeves specially designed 

for the opening of the roofing paper in order 

to insure it is airtight. The emission 

line must be level. 

Fig. 22 Emissions Connection to Central 

Roof Heating 

Follow the installation instructions for the respective emissions system! 

4.2.15 Connecting the Condensed Water Drain 

Lay plastic piping (min. Ø 32 mm or larger that leads to the drain) app. 2 cm under 

the condensed water drain connection. Do not place a permanent connection on the 

siphon in the boiler as this hinders maintenance. 

4.2.16 Neutralisation 

• Fill the boiler siphon to avoid flue gases from escaping into the room. 

• The condensed water drain must not be sealed. 

• The emission pipe should have a minimum slope of 3 cm per meter 

and a maximum horizontal length of 5 meters. 

• Disposing of condensed water via rain gutters is not permitted. 

• Condensed water lines must be installed according to regulation. 

ATV Bulletin M 251 regulations and state provisions apply! A pH balancing system 

can be installed retroactively for the Bruns wall boiler. A neutralization system is required 

for boiler capacities exceeding 25 kW. Regional regulations for running condensed 

water into the canalisation system are a deciding factor. Neutralisation granulates 

must be checked yearly by the operator and if necessary, renewed. 

- 21 - 





4.2.17 General Instructions for the Electrical Connection 

• This should only be performed by a licensed professional! 

• Make sure the unit is disconnected from electricity before beginning! 

Life threatening danger! 

• In Germany, the VDE and local regulations must be followed when installing. 

• The condensing gas boiler must be connected to an emergency shut 

down switch. 

• All components must follow VDE regulations. 

• Attention! Life threatening danger! Connection to the main power supply 

(230V) should not be made until all remaining control components 

have been fully wired! 

4.2.18 Electrical Connection 

Remove the front cover from unit. To do 

this, remove the two screws at the bottom 

on the front of the unit. Hold the bottom 

of the cover and pull toward you. 

The front cover can then be pulled up 

and out. 

Remove the screws, 2 on top and 2 on 

the bottom of the terminal strip cover and 

slide the cover out. 

- 22 - 

Remove the cover from the built-in slot in 

the controller. 

Screws 

Screws 




1 

2


1 

Screw 

Screw 

2 

You can lead additionally required cables 

into the unit through the cable opening on 

the bottom of the unit. 

Lay the cables as follows: 

• Lay current-carrying wires and 

sensor leads separately. Use the 

lower clamp for the 230 V wire and 

the upper clamp for the sensor 

lead and the bus line. 

• The clamps serve as stress relief. 

Make sure that the cables are long 

enough to be mounted without placing 

strain on them. 

4.2.19 Pin Assignment on the Terminal Strip 

Remove the two screws on the left of the 

operation panel. To open the panel, lift 

up lightly on the left side. You can then 

clap it open it to the right. 

Sensor Lead 

230 V Wires 

Make sure the electricity is disconnected before you begin! 

BOY III Combi comes with an integrated and preinstalled three-way valve 

- 23 - 

o r g o r w ew eo r w eg b l g r / gG e 

B W A F B U S 3 - W e Ng e t z 

V e n t i l 

N 

N 

B W 

= D H W S e n s o r 

A F 

= O u t d o o r T e m p . S e n 

B U S 

= H e a t i n g C o n t r o l l e r 

3 - W e g = e 3v -e W n t a i l y - V a l v e 

N e t z 

= G r i d c o n n e c t i o n ~ 2 




L


5 Start up 

5.1 Filling and Ventilating the Heating System 

The condensing gas boiler is not yet ready for operation! 

Fill the heating system to a maximum water pressure of1.5 bar! 

Ventilate the entire heating system via the installed ventilation valves on the 

radiators, floor heaters and so on. Keep the pressure at 1.5 bar while ventilating. 

5.2 Ventilating the Unit 

The gas line must be connected prior to 

ventilating the unit! 

Open the quick-aspirator on the pump 

app. two rotations. Wait until the air is 

gone from the quick-aspirator. Leave the 

aspirator open! 

- 24 - 

Activate the electrical supply by turning 

on the heater’s emergency switch. The 

unit’s circulating pump will then start up. 

Let the unit run with the gas main closed! 

Do not open the gas main! The unit will 

display an error code while the gas main 

is closed. Do not dejam! 

Open the manual aspirator on the top of 

the unit. Close this one as soon and the 

air is gone and water comes out. 





5.3 Ventilating the Lower/Standing Reservoir (optional) 

To ventilate the heat exchanger’s heating 

coil in the lower/standing reservoir, you 

must operate the three-way valve manually. 

To do this, remove the safety splint 

from the three-way valve ... 

Press the valve pin into the valve with a 

pair of pliers. The valve is now set to 

drinking water mode. The air in the drinking 

water heating coil can thus dispel 

from the unit via the aspirator. 

Re-establish the gas supply by opening 

the gas main. 

- 25 - 

and pull the motor off the valve. 

After successfully ventilating the unit, replace 

the motor onto the valve. 

Dejam the condensing gas boiler by holding 

down the III button. 





5.4 Start up 

After successfully ventilating and dejamming the unit, it will start in drinking water 

mode (if available); otherwise it will start in hot water mode. To start in hot water 

mode or in drinking water mode, the unit requires a certain level of heat. This can be 

done by opening the thermostats on the radiators. If an error occurs during the start 

up phase, it will be shown on the display (see error code list). 

5.4.1 Performance of the Unit Test Routine upon Start up 

After turning on the unit, a manual reset of every 12/24 hours, the control unit will 

perform a start up test routine. The 12/24 hour reset is dependent upon whether or 

not the heating demands require it. 

No heating demands: The control unit will reset every 12 hours 

Heating demands: The control unit will reset every 24 hours 

During the start up test routine, the three-way valve, if there is one, is switched to 

drinking water heating mode and directly after back to central heating mode, regardless 

of the previous position of the valve. This way, one complete pass is made by 

the valve, which keeps the valve from seizing. The circulation pump is also turned on 

during the test routine. 

5.5 (Pre) Setting the Boiler 

5.5.1 CO2 Boiler Settings 

The unit must be in chimney sweep 

mode (Ch. 6.3.8) when setting the CO2- 

levels. 

The amount of CO2 in the unit can be set 

with the adjusting screw on the gas 

valve. 

With liquid gas, the starting load must be 

change from 50% up to 60%. 

The CO2 – content must lie between the following levels, regardless of load: 

Gas Type CO2-Wert 

Natural Gas 8,5 – 9,0 % 

Liquid Gas 10 – 10,5 % 

- 26 - 





5.5.2 Gas Throughput Table / Connection Pressure 

Gas Type Load Area 

Gas Flow rate 

(l/min) Connection 

Pressure 

Min. Max. 

LL(L)-Gas 5,1 – 22,8 kW 11,6 50,1 20 mbar 

E(H)-Gas 5,1 – 22,8 kW 10,0 43,3 20 mbar 

Liquid Gas 5,1 – 22,8 kW 8,0 34,6 50 mbar 

Heating value: Natural Gas LL(L) = 8,83kWh/m³; Natural Gas E(H) = 10,22 kWh/m³; Liquid Gas = 12,78 kWh/m³ 

The above gas type values may vary regionally. Please ask your energy provider for 

the heating values as necessary. 

5.5.3 Changing Gas Types 

Changing gas types does not require any adaptations to the unit. Simply adjust the 

CO2 Level (Ch. 5.5.1) to the respective gas type. 

- 27 - 




Operating the Controls 

6 Operating the Controls 

6.1 Description of the Control Panel 

T a s t4 e 

T a s t 5 e 

L E D 1 L E D 2 L E D 3 

T a s t e1 2 3 

I II III 

8.8.8. 

S e g m e Cn t B D 

T a s t 6e 

L E D 4 L E D 5 

P u n k t C B 

D 

6.2 LED Display Symbols 

T a s t 7e 

Taste 1 

Function Description 

Switch to summer mode/ Chimney sweep 

mode 

Taste 2 Installation Mode / Installation (+) Mode 

Taste 3 Dejamming/ End Mode/ Error Log 

Taste 4 Positive Set-point changes heating water 

Taste 5 Negative Set-point changes heating water 

Taste 6 Positive Set-point Changes Drinking Water 

Taste 7 Negative Set-point Changes Drinking Water 

LED 1 Summer Mode on / off 

LED 2 Display Installer / Installer (+) Mode 

LED 3 Display Error 

LED 4 

LED 5 

Segment 

B / C / D 

Heating Water Requirements on / off 

Anti-Cycling on / off 

Drinking Water Heating Demands on / off 

Anti-Cycling on / off 

Display Temperature, Parameters, Error 

Codes 

Punkt D Display Flame detector (Flame on / off) 

Symbol Meaning Symbol’s Reference Name 

Central Heating Central Heating-Symbol 

Drinking Water 

Domestic Hot Water 

DHW-Symbol 

Test Mode TM-Symbol 

Degrees Celsius Celsius-Symbol 

Index Index-Symbol 

Error E-Symbol 

Parameter Parameter-Symbol 

50 Normal Display for the Value 50 

150 Point Display for the Value 100 

25 Point Display for the Value 200 

Flame Last point shows that there is a flame 

- 28 - 





6.3 Controller Functions and Operating Status 

In the followings sections, the control functions as well as the displays for the different 

operating modes will be described. 

6.3.1 Start up 

� If an external Open Therm controller or set-point calculator is installed, 

various settings can be made via the room controller/ set-point calculator. 

Follow the unit’s description 

● The symbols used here such as , are examples; they may differ 

from your display! 

After switching on the electrical supply, the software versions for the different components 

are shown in the following order during start up: 

Display Time 

Software Version MMI Display 2 Seconds 

Software Version CVBC (HuP) Display 2 Seconds 

Software Version CVBC (LuP) Display 2 Seconds 

Software Version CVBC (EEPROM) Display 2 Seconds 

6.3.2 Standby Mode 

In standby mode, the ignition mechanism is turned off, the gas valve is closed and 

the pump turns off when the cool-down is complete. If there is no active heating demand 

and no error code is displayed, the following information will be on the display. 

Display Display Element 

Central Heating Warm-up 

Temperature 

6.3.3 Flame Detector 

Segment B and C 

Celsius-Symbol Segment D 

When there is a flame, this is shown by a point display. 


Flame On Point Display D 

- 29 - 





6.3.4 Central Heating Mode 

6.3.4.1 Operating the Central Heater 

If the thermostat closes or the optional Open Therm unit registers a heating demand, 

the following information will be displayed. 


Central Heating Warm-up Temperature Segment B and C 


Central Heating Demand On LED 4 = On 

Central Heating Demand Off LED 4 = Off 

6.3.4.2 Anti-Cycling Central Heating 

on / off 

When the central heating demand is no longer present, the anti-cycling function is activated. 

When in this mode, the following information will be displayed. 


Central Heating Warm-up Temperature 



Central Heating Anti-Cycling LED 4 = Blinking 

blinking 

When the heating demand is over, no new heating demands will go through the unit 

for 90 seconds. This function lengthens the boiler’s life-span. 

6.3.5 Drinking Water Mode 

6.3.5.1 Operating the Drinking-Water Heater 

When there is a demand on the drinking-water heater, the following information will 

be displayed. 


Drinking-water Temperature Segment B and C 


Drinking-water Demand On LED 5 = On 

Drinking water Demand LED 5 = Off 

- 30 - 

on / off 





6.3.5.2 Anti-Cycling Drinking-Water Heater 

When the demand for drinking-water is over, the anti-cycling function is activated. 

When in this mode, the following information will be displayed 


Drinking-Water Temperature Segment B and C 


Drinking-Water Heater Anti-Cycling LED 5 = Blinking 

blinking 

When the heating demand is over, no new heating demands will go through the unit 

for 90 seconds. This function lengthens the boiler’s life-span. 

6.3.6 Changing the Set-point 

6.3.6.1 Changing the Set-point for Central Heating 

The set-point for heater water can be changed with 

the 4 and 5 buttons. When the heating water setpoint 

is changed, the following information will be 

displayed. 


Set-point, Central Heating Segment B and C 


T a s t4 e 

L E D 4 

T a s t5 e 

blinking 

If the value is not changed within 5 Seconds, the display returns to the previous 

mode and the new set-point will be saved. 

6.3.6.2 Changing the Set-point for the Drinking-Water Heater 

The set-point for the drinking-water heater can be 

changed with the 6 and 7 buttons. When the drinking-water 

set-point is changed, the following information 

will be displayed. 


Set-point, Central Heating Segment B and C 


T a s t 6e 

L E D 5 

T a s t 7e 

blinking 

If the value is not changed within 5 Seconds, the display returns to the previous 

mode and the new set-point will be saved. 

- 31 - 





6.3.7 Summer Mode 

Summer mode can be activated by quickly pressing 

the 1 button (less than 1 second). In the table below, 

the information for summer mode status is 

shown. 


Summer mode On LED 1 = On 

Summer mode Off LED 1 = Off 

6.3.8 Chimney Sweep Mode 

Pressing the 1 button for 3-5 seconds until the display 

(E99) starts blinking. The unit will then run at 

max. capacity (100%). The capacity can be reduced 

to 0% with the 4 and 5 buttons. 


E-Symbol Segment B 

Display Code 99 Segment C and D 

T a s t e1 

L E D 1 

I 

T a s t e1 

L E D 1 

I 

on / off 

blinking 

T a s t4 e 

L E D 4 

T a s t5 e 

The chimney sweep function can be turned off by pressing the 3 button, or after 30 

min. the unit switches back to the normal heating mode automatically. 

6.3.9 Installer Mode 

The installer mode can be activated by quickly 

pressing the 2 (less than 1 second). In the table below, 

the respective information is shown. 


Index symbol alternates with the setpoint. 

After changing the set-point, it 

will appear after 2 seconds 


Value of the chosen index Segment B, C and D 

Installer Mode LED 2 = On 

In the following table (next page), the available information is shown. 

- 32 - 

T a s t e2 

L E D 2 

II 

alternating 




on


Set-point Information 

1 Actual flame current 

2 Actual supply temperature of the central heater 

3 Actual return flow of the central heater 

4 Actual temperature of the drinking-water 

5 Water pressure 

6 Type of use 

7 Actual temperature of the flame pipe or TTB 

8 Throughput speed of the drinking-water (Hz) 

9 Current control-set-point 

10 Current outside temperature (OTC-Temperature) 

The set-point can be raised by 1 by quickly pressing 

the 1 button (less than 1 second). When the 

counter has reached its highest value, it will drop 

T a s t e2 

down to 0. II 

Installer-mode is exited by quickly pressing the 3 

button (less than 1 second). The installer mode also 

has a time out function that exits the installer mode 

after one minute of inactivity. This function is also 

turned off if the electrical supply is interrupted. 

6.3.10 Installer (+) Mode 

T a s t e3 

The installer (+) mode can be activated by holding 

the 2 button for longer than 3 seconds. The displayed 

information’s format is shown in the following 

T a s t e2 

display. II 


Parameter symbol alternates with the 

index symbol. After changing the setpoint, 

it will appear after 2 seconds 

Segment B 

Parameter value for the chosen index Segment B, C and D 

Installer (+) Mode LED 2 = Blinking 

- 33 - 

L E D 2 

L E D 3 

III 

L E D 2 

alternating 

blinking 





6.3.10.1 Installer (+) Parameter List 

The following values will be displayed and can be changed. Values with the symbol 

cannot be changed! 

Index Parameter Description Area 

1 CH Slope 

2 

CH Anticycle 

Time 

3 CH Kp 

4 CH Ki 

5 DHW Kp 

6 DHW Ki 

7 

Ignition 

Level 

8 Fan Kp 

9 Fan Ki 

11 CH set-point 

12 

13 

14 

CH Pump 

Overrun 

DHW setpoint 

CH max. capacity 

Central factor for the ascent/descent 

of the edge; defines the temperature 

rise in the warm-up 

cycle of the central heating demand 

Central heater anti-cycling time. 

During this period the CVBC will 

not accept any further central 

heating demands. 

Proportional control factor central 

heater 

Integral control factor central 

heater 

Proportional control factor for the 

drinking-water heater 

Integral control factor for the 

drinking-water heater 

Ignition level with which the boiler 

is ignited 

Proportional control factor for the 

fan controller 

Integral control factor for the fan 

controller 

The actual set-point of the 

central heater 

Pump overrun time for the central 

heater 

The actual set-point of the drinking-water 

heater 

The maximum capacity of the 

central heater 

- 34 - 

Default 

V1042 Esys2042 

0-60 °C/Min. 5 °C/Min 5 °C/Min 

0-900 sec. 90 Sec. 2 min. 

0-255 3 3 

0-255 95 95 

0-255 5 5 

0-255 95 95 

30-100 % 50% 33% 

0-255 13 13 

0-255 150 150 

30-80 °C 80 °C 70 °C 

1-20 Min. 7 Min. 7 Min. 

35-65 °C 60 °C 55 °C 

60-100% 90% 87% 





Index Parameter Description Area 

15 

16 

17 

18 

19 

DHW Pump 

Overrun 

CH Hysteresis 

DHW Hysteresis 

CH Max. 

Set-point 

Pump overrun time for the drinking-water 

heater 

Hysteresis of the central heater’s 

set-point during modulation 

Hysteresis of the drinking-water’s 

set-point during modulation 

Maximum value at which the 

central heater’s set-point may be 

set 

The values can be changed with the 6 and 7 buttons, 

respectively. 

When changing the value, the LED 3 will blink, 

which shows that the value can be confirmed by 

pressing the 3 button. If the value has not been 

confirmed within 5 seconds, the original value is restored 

and no new value will be saved. 

1-10 4-5 

Default 

V1042 Esys2042 

30-180 Sec. 30 Sec. 30 Sek. 

2-10 °C 3 °C 7 °C 

2-10 °C 7 °C 7 °C 

30-85 °C 85 °C 80 °C 

T a s t 6e 

L E D 5 

T a s t 7e 

T a s t e3 

L E D 3 

III 

LED blinkt 

Installer (+) mode will be exited after one 1 min. of inactivity. If LED 3 is off, installer 

(+) Mode can also be exited by quickly pressing the 3 button (less than 1 second). 

- 35 - 




Malfunctions and Errors 

7 Malfunctions and Errors 

7.1 Error Mode 

If there is an error the following information are displayed 


Error code Segment C and D 

E-Symbol Segment B 

Errors can be reset LED 3 = Blinking 

Errors that can correct themselves LED 3 = Off 

If the error can be reset, press the 3 button and it will reset. 

7.2 Error Code List 

T a s t e3 

L E D 3 

III 

blinking / off 

The error codes are split into two groups; shut down codes and blocking codes. 

7.2.1 Shutdown Codes 

Code Description Solution 

1 

2 

3 

5 

11 

26 

Shut off signal after the flame is out and all 

ignition attempts have failed. 

False flame signal. A flame signal is recognised 

without the gas valve being open. 

Excess temperature signal from the excess 

temperature thermostat. If the thermostat 

is open, it will cause an error to occur. 

Speedometer error. The controller requires 

a certain fan rotation, but is not receiving a 

(correct) speedometer signal. 

Check the gas supply and open any closed 

valves. 

Check the gas valve. If there is a flame, replace 

the gas valve. Check the ionization and replace 

as needed. 

Check the boiler settings (draft curve, max. Temperature, 

differential gap). Check the supply and 

return flow sensors. 

Check the connection between the fan and the 

automatic firing device. Check the fan and replace 

as needed. 

Errors during the first temperature check. 

Initially, the pump’s controller will turn on to 

equalize the supply and return flows to with Check the supply and return flow temperatures. 

in 5 °C of each other. The sensors have Check the sensors and replace as needed. 

not reached the same values within app. 4 

minutes. 

The controller has lost the flame signal 4 

times within 240 sec. There is something 

wrong with the flame recognition’s reliability. 

- 36 - 

Check the ionisation and clean or replace as 

needed. 





7.2.2 Locking Codes 

The boiler controller also recognises errors that may lead to the heating demand 

lockup, but does not recognise errors that may lead to a shutdown. If the error is resolved, 

it disappears, but will be recorded in the error log. The descriptions of these 

codes are as following: 


30 

31 

32 

33 

34 

35 

Central heating sensor is not within normal 

parameters (short circuit). If the NTCsensor 

is not within normal parameters and 

remains in this state for longer than 10 sec., 

Check the supply sensor and replace the univer 

a warning will be displayed. If the sensor 

sal sensor as needed. 

returns to normal parameters, the warning 

disappears. The warning causes the system 

to shut down. Heating demands are 

deactivated. 

Central heating sensor is not within normal 

parameters (line error). If the NTC-sensor is 

not within normal parameters and remains 

in this state for longer than 10 sec., a warn 

Check the supply sensor and replace the univering 

will be displayed. If the sensor returns 

sal sensor as needed. 

to normal parameters, the warning disappears. 

The warning causes the system to 

shut down. Heating demands are deactivated. 

Domestic warm water sensor is not within 

normal parameters (short circuit). If the 

NTC-sensor is not within normal parameters 

and remains in this state for longer than Check the reservoir sensor. If no reservoir 

10 sec., a warning will be displayed. If the sensor is connected, check the resistance on the 

sensor returns to normal parameters, the end plate and replace as needed. 

warning disappears. The warning causes 

the system to shut down. Heating demands 

are deactivated. 

Domestic warm water sensor is not within 

normal parameters (line error). If the NTCsensor 

is not within normal parameters and 

remains in this state for longer than 10 sec., Check the reservoir sensor. If no reservoir 

a warning will be displayed. If the sensor sensor is connected, check the resistance on the 

returns to normal parameters, the warning end plate and replace as needed. 

disappears. The warning causes the system 

to shut down. Heating demands are 

deactivated. 

This error is caused by the electrical supply 

being too low (less than 185 V alternating 

current). 

The power frequency shows a deviation of 

more than +/- 5 %. 

- 37 - 

Check the electrical current. If the electrical supply 

returns to normal, the error will disappear 

within 10 sec. 

Check the power frequency. If the power frequency 

returns to normal, the error will disappear. 






37 Water pressure is too low. 

41 

43 

44 

47 

Water pressure signal time out. The water 

pressure value is not being refreshed often 

enough. 

Central heating- return flow sensor is not 

within normal parameters (short circuit). If 

the NTC-sensor is not within normal parameters 

and remains in this state for longer 

than 10 sec., a warning will be displayed. If 

the sensor returns to normal parameters, 

the warning disappears. The warning 

causes the system to shut down. Heating 

demands are deactivated. 

Refill water (1.6 bar). Check the water pressure 

on the display and match it with the pressure 

gauge. If the difference is larger than 0.6 bar, replace 

the water pressure sensor. 

Remove the water pressure sensor and make 

sure the opening for the sensor is clear of obstructions. 

Clean as needed and install a filter in 

the heating circuit beneath the boiler. 

Check the water pressure sensor connection and 

replace the universal sensor as needed. 

Check the return flow sensor and replace as 

needed. 

Central heating- return flow sensor is not 

within normal parameters (line error). If the 

NTC-sensor is not within normal parameters 

and remains in this state for longer than 

Check the return flow sensor and replace as 

10 sec., a warning will be displayed. If the 

needed. 

sensor returns to normal parameters, the 

warning disappears. The warning causes 

the system to shut down. Heating demands 

are deactivated. 

Combination error. Either the water pressure 

sensor or the supply sensor is defective 

or the cable has been interrupted. 

Check the universal sensor (water pressure and 

supply sensors against the automatic firing 

device. 

All errors are recorded in the error log and organised in relation to the number of operation 

modes. The error codes 10-22 are not visible (they are part of the safety 

core). 

- 38 - 





7.3 Error history Mode 

The Error history mode can be activated by holding 

the 3 button longer than 3 seconds. The information’s 

displayed format is shown in the following 

T a s t e3 

table III 


E-Symbol alternating with the 

Index-Symbol 

Segment B 

Error code for the chosen index Segment C and D 

Error Log Mode LED 3 = Blinking 

L E D 3 

alternating 

blinking 

Error log mode can be exited by quickly pressing the 3 button (less than 1 second). 

Error log mode also has a time out function that exits the installer mode after 30 

minutes of inactivity. This function is also turned off if the electrical supply is interrupted. 

7.4 Log Resistance Values for the Boiler and Reservoir Sensors 

If there is an error in the boiler or reservoir sensors’ transmittal, it can be determined 

via the sensors’ resistance values. 

Temperature °C 

Nominal Value k 

RT 2333 640 6123 

Temperature °C 

Nominal Value k 

RT 2333 640 6123 

-40 309,5 35 8,055 

-35 229,4 40 6,653 

-30 171,7 45 5,524 

-25 129,7 50 4,609 

-20 98,82 55 3,863 

-15 75,94 60 3,253 

-10 58,82 65 2,752 

- 5 45,91 70 2,337 

0 36,10 75 1,994 

5 28,59 80 1,707 

10 22,97 85 1,467 

15 18,29 90 1,266 

20 14,72 95 1,096 

25 12,00 100 0,9522 

30 9,805 

- 39 - 




Maintenance 

8 Maintenance 

8.1 General Instructions for Maintenance 

• Cleaning and maintenance should only be performed by a licensed 

professional. 

• Close all gas and heating and drinking water valves before beginning! 

• Make sure the unit is disconnected from electricity before beginning! 

8.2 Cleaning the Condensed Water Siphon 

The condensed water siphon should be cleaned in the following intervals: 

Yearly: the siphon connection on the bottom 

of the boiler. Make sure to have a 

collection container ready to collect the 

runoff condensed water. Clear obstructions 

and dirt from the siphon, replace 

the cover and test the water tightness of 

the connection. 

Every two years: completely remove and 

clean the siphon. Remove the upper 

connection to the siphon and pull down 

on the siphon. Remove the siphon, with 

hose, from the boiler, disconnect it and 

rinse thoroughly with clear water. Install 

the siphon by reversing this process. 

8.3 Cleaning the Combustion Chamber 

Clean the combustion chamber yearly. 

Remove the fan’s intake hose 

- 40 - 




Maintenance 

Use a flat spanner (SW 27) to remove 

the gas valve connection. Make sure the 

washer does not fall out of the connection. 

- 41 - 

Disconnect the ignition plug, ionisation 

and PE cable (ground) from the boiler. 

Use a flat spanner (SW 13) to remove 

the control unit’s securing screw. 




Maintenance 

Remove the control unit by pulling to the 

right. 

Carefully remove the burner. Carefully 

clean the heat exchange surfaces in the 

combustion chamber as well as the burner 

head with a nylon brush. Do not use a 

wire brush, sharp objects and so on! 

Remove the burner screws. 

nstall the components in reverse order. Make sure that all connections are screwed 

tight and well connected. Check to make sure the gas valve connection is airtight. 

The washer may need to be replaced. 

After successful maintenance, restart the unit. Make sure the unit is running 

free of errors after maintenance. 

- 42 - 




Technical Data 

9 Technical Data 

9.1 Circuit Diagram 

A u t o m a t i c F i r i n g D e v i c e S 4 9 6 5 C V B C C o n t r o l B o a r d M M I 

X 1 X 2 X 3 X 4 X 5 

X 1 X 1 2 

X 1 1 

G a s V a l v e 

2 3 4 5 6 

1 

1 2 3 4 5 6 7 8 

2 3 

2 3 4 5 6 1 

I g n i t i o n 

I o n i s a t i o n 

1 

1 2 3 4 5 6 7 8 9 1 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 

s w 

r o 

w e 

b l 

b l 

s w 

b l 

b r 

r o 

b l 

s w 

s w 

r o 

s w 

b r 

b l 

b l 

w e 

w e 

b r 

s w 

r o 

w e 

s w 

l i 

b r 

s w 

r o 

w e 

w e 

r o 

b l 

b l 

b r 

l i 

w e 

s w 

g r / g e 

Z 1 

Z 2 

s w 

w e 

F 1 

r o 

w e 

b l 

s w 

F 2 

F 3 

r o 

s w 

b l 

F 4 

b r 

s w 

- 43 - 




M 2 

s w 

b l 

g r / g e 

M 1 

r o 

s w 

b r 

b r 

g r / g e 

b l 

g r / g e 

b r 

b r 

b l 

b l 

w e 

s w 

b r 

w e 

w e 

r o 

b r 

s w 

F 5 M 3 

Z 1 I g n i t i o n E l e c t r o d e 

Z 2 I o n i s a t i o n E l e c t r o d e 

F 5 D H W S e n s o r 

M 1 B l o w e r 

M 2 C i r c u l a t i n g P u m p 

M 3 T h r e e - W a y - V a l v e 

F 1 C o m b i S e n s o r ( w a t e r p r e s s u r e & t e m p e r a t u r e ) 

F 2 E x h a u s t T C O 

F 3 F l o w M e t e r D H W 

F 4 T e m p e r a t u r S e n s o r ( r e t u r n )


9.2 Technical Data 

2 1 0 

4 3 

1 0 8 

1 5 4 

2 0 5 

2 4 3 

1 6 5 

3 0 5 

3 9 5 

3 9 5 

8 5 

1 2 5 

850 

150 

20 

295 

- 44 - 

S R A K 

V L S V R L 




G 

S R A K 

V L W WS V K W 

R L 

G


BOY III Solo / Combi 

Width / Height / Depth mm 395 / 650 / 295 

Weight kg 35 

CE- number CE- 0045BRKD 1002 

Type of unit (licensed for...) B 23 & C 63x 

Preset gas type natural gas type LL 

Rated heating range of performance 50/30°C kW 5,1- 22,8 

Rated heating range of performance 80/60°C kW 4,6 - 20,1 

Rated heating load kW 4,8 - 21,8 

Degree of efficiency 50°/30°C % 106,3 

Max. capacity in warm water mode kW 24 

Continuous output of warm water L/ min 9,8 

Adjustment range for warm-up temperature °C 30 

Permitted operational temperature °C 90 

Permitted operational pressure bar 3 

Residual supply pressure Pa 100 

Unit water capacity L 3,5 

Emissions connection mm 80/125 

Emissions material PPs bis 120°C 

Emissions output oben 

HV / HR connection AG ¾“ flat sealing 

Gas connection IG ½“ flat sealing 

Natural gas connection pressure mbar 20 

Liquid gas connection pressure mbar 50 

Electrical connection V/Hz 230/50 

Emission Values Partial Load Full Load 

Emissions mass flow rate 80/60 °C g/s 1,87 7,98 

Emissions temperature 80/60 °C °C 68 76 

Residual headroom for air and 

emissions system 

80/60 °C Pa 100 100 

Emissions mass flow rate 50/30 °C g/s 1,87 7,98 

Emissions temperature 50/30 °C °C 68 76 

Residual headroom for air and 

emissions system 

50/30 °C Pa 100 100 

Natural gas CO2-content Vol.% 9,5 9,5 

Liquid propane CO2-content Vol. % 10,0 10,3 

- 45 - 





10 Declaration of Conformity 

- 46 - 




Notes 

- 47 - 




Notes 

- 48 -

Installation and Operating Instruction

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