AIR CONDITIONING - Rafstjorn

A/C UNITS
COMPACT-AIR
230/1/50-60 400/3/50
Index 31A
Edition 03.04
AIR CONDITIONING
PRECISION A/C UNITS
OPERATING INSTRUCTIONS

E/0304/31A/2

Contents
Page
Introduction 4
Technical Data 6
Capacity Diagrams 8
Dimensions 13
1. Unpacking and Inspection 14
2. Unit Identificaton 15
3. Operating Principle 16
4. Precautions 18
5. Safety Considerations 18
6. Precautions when handling the Unit 19
7. Installation 19
8. Vibrations 24
9. Mechanical Parts 24
10. Cooling Components 24
11. Motors 25
12. Control, Monitoring and Safety Components 26
13. Electrical Connections 28
14. Start-up 29
15. Adjusting the Temperature 29
16. First Checks after starting the Unit 30
17. Switching off 30
18. Maintenance 30
19. Inactivity 31
20. Options 32
21. Residual Hazards and Emergency Information 34
22. Disassembling the Unit 38
23. Faults, probable Causes, possible Remedies 39
The manufacturer reserves the right to make alterations without notice.
E/0304/31A/3

Introduction
The following information is supplied in accordance with Standards:CE73/23,CE93/
68,CE89/392:
MANUFACTURER'S NAME AND ADDRESS
STULZ GmbH
Holsteiner Chaussee 283
22480 Hamburg
DATA REGARDING THIS MODEL
Air conditioner for telecom application
YEAR OF MANUFACTURE
As shown on the technical name plate on the unit
HOW TO CONSULT THIS MANUAL
This document contains general informations valid for all models of the series. Further
informations like wiring diagrams etc. will be delivered with each unit.
THIS MANUAL IS INTENDED FOR
OWNER OF THE APPLIANCE
PERSON RESPONSIBLE FOR ITS INSTALLATION
PERSON RESPONSIBLE FOR MANAGING THE PRODUCT
PERSON RESPONSIBLE FOR ORDINARY MAINTENANCE
PERSON RESPONSIBLE FOR ITS DISASSEMBLY
PURPOSE OF THE INFORMATION CONTAINED IN THIS MANUAL:
CORRECT HANDLING
performed by unskilled personnel
CORRECT INSTALLATION
performed by skilled personnel;
CORRECT START-UP
performed by personnel trained by STULZ;
CORRECT MANAGEMENT
performed by skilled personnel;
CORRECT MAINTENANCE
performed by skilled personnel;
CORRECT ORDER FOR SPARE PARTS, made by skilled personnel;
CORRECT DISPOSAL OF THE PRODUCT, made by skilled personnel.
RESTRICTIONS TO THE USE OF THIS MANUAL
They apply to any operations that must be performed by highly skilled personnel.
E/0304/31A/4

WHERE AND HOW TO STORE THIS MANUAL
Inside the electric cabinet or together with any other literature concerning the equipment
which utilizes the product, provided it is a dry and clean place.
In the event of the manual being misplaced or damaged, the customer may require, for a
fee, a new manual, by quoting the model and serial number shown on the technical
name- plate, by contacting your local STULZ partner.
CURRENT TECHNOLOGY
This manual reflects the state of the art existing at the time the product is marketed and
shall not be deemed to be inadequate for the sole reason that it has not been updated as
a result of any new experience.
UPDATES
STULZ reserves the right to update the product and relevant manual without being
required to update previous products and manuals other than in exceptional
circumstances. To require or receive any updates of the instructions manual or
amendments thereto, which shall be deemed to be an integral part of the manual, please
contact your local STULZ partner.
FOR FURTHER INFORMATION
Please contact your local STULZ partner.
Any suggestions or recommendations made by installers or users of the product for the
purpose of improving the product or the contents of this manual, will be greatly
appreciated by the Manufacturer.
IN THE EVENT OF SALE OF THE PRODUCT
Please advise STULZ GmbH of the address of the new owner so as to enable the
dispatch of any updates to the manual, otherwise STULZ GmbH shall be relieved of any
subsequent liabilities
E/0304/31A/5

Technical Data CVC 07 002yy - CVC 20 002yy (at 50 Hz)
CVC 07 0 02yy
CVC 14 0 02yy
CVC 20 0 02yy
Cooling capacity L35L35 - (DIN3168)
Cooling capacity L35L50 - (DIN3168)
Refrigerant
W
W
750
580
R134a
1400
1170
R134a
2000
1700
R134a
Condenser fan
Number/Type
Air flow
m³/h
1/Ø190 radial
400
1/Ø220 radial
650
1/Ø225 radial
850
Evaporator fan
Number/Type
Air flow
m³/h
1/Ø150 compact
(axial)
220
1/Ø190 radial
390
1/Ø190 radial
390
Refrigerant charge
External operating limit temp. min/max
Cabinet operating limit temp. min/max
Extern noise level **
Internal noise level ***
Duty cycle
Weight
Height / Width / Depth
kg
°C
°C
dB(A)
dB(A)
%
kg
mm
0.35
-20/+55*
+25/+45
62
52
100
25
634/308/227
0.55
-20/+55*
+25/+45
73
62
100
42
1004/417/251
0.65
-20/+55*
+25/+45
71
62
100
44
1004/417/251
Electrical Data
Power Supply Code
Nominal voltage
Tolerance on voltage
Phase
Nominal frequency
Tolerance on frequency
Power consumption L35L50
Locked rotor current (LRA)
Operating current (OA)
V
ph
Hz
W
A
A
20
230
±10%
1
50-60
± 2%
400
16
2.3
20
230
±10%
1
50-60
± 2%
850
17
4.1
20
230
±10%
1
50-60
± 2%
1190
20
6.1
Condenser Fan
Power consumption
Operating current
W
A
61
0.27
90
0.4
165
0.73
Evaporator Fan
Power consumption
Operating current
W
A
29
0.15
61
0.27
61
0.27
* 50°C at 60 Hz
** measured at 2m distance from the unit front side (condenser side), free-field, external temp. higher than 40°C
*** measured at 2m distance from the unit back side (evaporator side), free-field, external temp. higher than 40°C
E/0304/31A/6

Technical Data CVC 28 002yy - CVC 41 002yy (at 50 Hz)
CVC 28 0 02yy
CVC 41 0 02yy
Cooling capacity L35L35 - (DIN3168)
Cooling capacity L35L50 - (DIN3168)
Refrigerant
W
W
2700
2300
R134a
3900
2900
R134a
Condenser fan
Number/Type
Air flow
m³/h
1/Ø250 radial
1150
1/Ø250 radial
1150
Evaporator fan
Number/Type
Air flow
m³/h
1/Ø220 radial
650
1/Ø250 radial
1150
Refrigerant charge
External operating limit temp. min/max
Cabinet operating limit temp. min/max
Extern noise level **
Internal noise level ***
Duty cycle
Weight
Height / Width / Depth
kg
°C
°C
dB(A)
dB(A)
%
kg
mm
1
-20/+50
+25/+45
75
73
100
81
1234/509/382
1.05
-20/+50
+25/+45
75
75
100
86
1234/509/382
Electrical Data
Power Supply Code
Nominal voltage
Tolerance on voltage
Phase
Nominal frequency
Tolerance on frequency
Power consumption L35L50
Locked rotor current (LRA)
Operating current (OA)
V
ph
Hz
W
A
A
20
230
±10%
1
50-60
±2%
1450
35
7.5
42
400
±10%
3+N
50
±2%
1450
16
3
20
230
±10%
1
50-60
±2%
1770
46.5
8.3
42
400
±10%
3+N
50
±2%
1770
18
3.5
Condenser Fan
Power consumption
Operating current
W
A
152
0.69
152
0.69
152
0.69
152
0.69
Evaporator Fan
Power consumption
Operating current
W
A
90
0.4
90
0.4
152
0.69
152
0.69
* 50°C at 60 Hz
** measured at 2m distance from the unit front side (condenser side), free-field, external temp. higher than 40°C
*** measured at 2m distance from the unit back side (evaporator side), free-field, external temp. higher than 40°C
E/0304/31A/7

Capacity diagram CVC 07 002 yy (at 50 Hz)
Cooling capacity [W]
Inside
temp.
[°C]
Outside temperature [°C]
E/0304/31A/8

Capacity diagram CVC 14 002 yy (at 50 Hz)
Cooling capacity [W]
Inside
temperature
[°C]
Outside temperature [°C]
E/0304/31A/9

Capacity diagram CVC 20 002 yy (at 50 Hz)
Cooling capacity [W]
Inside
temp.
[°C]
Outside temperature [°C]
E/0304/31A/10

Capacity diagram CVC 28 002 yy (at 50 Hz)
Cooling capacity [W]
Inside
temperature
[°C]
Outside temperature [°C]
E/0304/31A/11

Capacity diagram CVC 41 002 yy (at 50 Hz)
Cooling capacity [W]
Inside
temp.
[°C]
Outside temperature [°C]
E/0304/31A/12

Dimensions
B
C
A
Type
CVC 07
CVC 14-20
CVC 28-41
A
634
1004
1234
B
308
417
509
C
227
251
382
E/0304/31A/13

1. Unpacking and Inspection
STULZ products are shipped ex-works. All units have been individually inspected in all
their parts and carefully packaged.
Immediately inspect the unit upon receipt, making sure it has been shipped in its proper
position. Note improper shipment on the shipping document.
We recommend you accepting merchandise subject to inspection.
UP
UP
UP
Check for damage and, if any, note this immediately on the shipping document. Remove
packing and check that the exterior casing is not scratched, marked or have signs of blows
and that no components are missing and that there are no traces of oil. Before throwing the
packaging away check that it does not contain documents or parts of the machine.
Any damage that is encountered must be notified to the carrier by registered letter within 8
days of receipt. The carrier is responsible for any damage caused during shipment. STULZ
is not responsible for damage caused to the merchandise by the shipper but will do all in
its power to assist customers in these situations.
N.B. This product may not be returned without prior written approval by STULZ.
For any assistance please contact your local STULZ partner.
NOTE: If installation of the product is not required immediately or the product needs
to be onforwarded to its final destination, replace it in its packing, after inspecting it,
and store it in a safe place.
WARNING! As an environmental concern, we recommend to recycle the
packing cartons and to separate them from any plastic.
E/0304/31A/14

2. Unit Identification
This unit can be correctly identified by the
technical name-plate containing all the
information for its correct use.
In addition to the manufacturer's identification
data and the product trade-marks, the nameplate
contains the following information:
The technical name-plate is embossed on a
plastic support which ensures high endurance
of the text even in particularly difficult
environments.
N.B. For any assistance or information
concerning the unit described in this manual,
knowledge of its serial number is essential.
Constructor
Model
Series
Date
Nominal voltage
Control voltage
Phase
Frequency
Trademark
This identifies the product family.
Product identification number.
Date on which the product is placed
on the market and date of
commencement of warranty.
Voltage to be supplied to the unit
Working voltage of the auxiliary
circuits if different from the voltage
rating.
Voltage phase
Voltage frequency.
Start/Run current
Current absorbed when starting the compressor. /
Current absorbed during operation at the permitted
maximum temperature
Cooling capacity
Unit cooling capacity with 35°C inside cabinet
temperature and 35°C ambient temperature conditions.
Power absorbed
Power absorbed by the unit with 35°C inside cabinet
temperature and 50°C ambient temperature conditions.
Automatic circuit breaker curve type C, Safety
fuse type aM
Rating of the automatic switch/safety fuse to be installed
by the installer.
Inside temperature
Minimum and maximum cabinet temperature where the
machine works and for which the machine was
designed.
Outside temperature
Minimum and maximum ambient temperature where
the machine works and for which the machine was
designed
Refrigerant charge
Quantity of refrigerant contained in the unit's
refrigeration circuit
Type of refrigerant
Brand name of the refrigerant used in the unit's cooling
circuit
Maximum pressure
Maximum pressure at which the refrigeration circuit
functions
Cabinet side protection IP
protection level in the direction of the cabinet
Ambient side protection IP
protection level in the direction of the ambient
Weight Empty weight of the machine
Duty Cycle Operational capacity of the unit
E/0304/31A/15

3. Operating Principle
STULZ conditioners are designed to cool electric cabinets with IP54 protection level and
they are suitable for the operation in industrial environments. Their use allows to eliminate
problems caused by high temperatures, dirt and humidity which are present in the
environment.
The unit, which is basically made up of a sealed cooling circuit where the refrigerant
circulates, is divided into two sections, hermetically separated from each other, where the
air in the environment and the air in the cabinet are treated without coming into contact
with each other.
The system operates as follows:
The compressor compresses the refrigerant gas bringing it to a high pressure and
temperature.
The hot gas, by going through the condenser, is cooled and liquefied thus releasing heat
to the air in the environment. Pushed through the capillary pipe, the liquid refrigerant loses
pressure, which makes it prone to evaporation. This takes place in the evaporator, where
the refrigerant absorbs the heat of the warm air from the cabinet, which is therefore cooled.
Condenser pressure
switch (proportional control)
Filter dryer
Capillary pipe
Condenser fan
Evaporator fan
Evaporator
Condenser
HP switch
LP switch
Compressor
Regulating
thermostat
E/0304/31A/16

Air flow inside the unit
Outdoor application
INTERNAL SIDE
EXTERNAL SIDE
Condenser
Evaporator fan
Condenser fan
Evaporator
Compressor
E/0304/31A/17

4. Precautions
The CVC series cooling units are designed to operate as a wall-type unit and in an upright
position. For all models the compressor is and must always be in an upright position.The
cooling units may not be used or transported in a position other than that for which they
have been designed.
WARNING!
Never run the machine if you have discovered leakage of the coolant fluid.
If traces of oil are present on the unit, which point to a loss of coolant, on the inside or the
outside, then the equipment must be thoroughly checked before starting the unit and, if
necessary, the technical department of your local STULZ partner should be contacted.
5. Safety Considerations
The installation and handling of cooling units may be hazardous as they form a pressurised
system with electric components.
Only skilled personnel may repair, inspect or maintain the cooling units.
All other operations must be performed by personnel who are experienced and qualified in
the maintenance of cooling systems.
Before servicing this unit, refer to the instructions contained in this manual, check the data
on the data plate and follow any other precaution to ensure optimum safety.
WARNING!
Never work on the unit without having disconnected the power supply
before!
E/0304/31A/18

6. Precautions when handling the Unit
To move this unit, when it is still packaged, use
a fork lift or a system using cables or chains.
When the packing is removed, use two M6
eyebolts, attaching them to the upper part of the
cooling unit, where appropriate holes have
already been arranged.
7. Installation
1 Unpack the unit taking care not to damage its exposed parts. Before discarding it,
check the packaging for any parts or documents. Check that the supply voltage is as
designated.
2 Check that:
- there is space enough for an easy application and installation, both inside and
outside the cabinet;
- the cabinet is at least of the IP54 type;
- the cabinet is clean on the inside;
- the cabinet is not in the proximity of heat sources or warm air flows;
- the inside of the cabinet allows a proper air circulation, preventing any recirculation.
It is important to prevent hot air expelled by the condenser fan from being even partially
sucked back in. This would cause continuous stoppages, commanded by the pressure
switches, reducing efficiency and increasing electricity consumption. Improper operation
of this type can quickly cause irreparable harm to the compressor.
WARNING!
Do not obstruct circulation by air being sucked into or expelled from the air
conditioner.
E/0304/31A/19

3 The cooling unit must be installed as high as possible;
4 If installed on a door, make sure the hinges can withstand the weight of the unit;
5 make sure the electric cable is not torn or damaged when the door is closed;
6 If the depth of the cooling unit prevents the door from being completely opened, arrange
a stopper for such a door.
7 Prior to servicing the cabinet, disconnect power supply to the same.
Prior to drilling holes or making cuts on the cabinet, make sure that holes, screws,
cables, etc. do not interfere with the equipment which has already been installed. Make
cuts on the cabinet panels by following the relevant template.
8 Once the anchoring holes have been drilled in the cabinet wall, mount the eyebolts to
handle the unit. the necessary cut-outs corresponding to the unit size can be seen on
the following pages.
9 Glue the adhesive gasket around the edges of the holes drilled on the cabinet;
10 Position the cooling unit at the cabinet and secure it with the appropriate screws.
adhesive gasket
threaded inserts
NOTE:
Compact-Air units are already provided with
threaded inserts, in correspondance with the
fixing holes at the cut-out.
Therefore the fixing holes at the cabinet wall
must not be provided with threaded inserts.
threaded inserts
Failure to comply with these requirements, in addition to affecting proper unit
operation, invalidates warranty coverage.
E/0304/31A/20

Cut-outs for CVC 07 002yy
308
68
172
68
590
92
634
95
150
27
12
261
4 x Ø8
2 x Ø22
42 45
17
24
260
24
E/0304/31A/21

Cut-outs for CVC 14 002yy - CVC 20 002yy
108.5
200 108.5
108,5 200
108,5
38,5 38.5
340
38,5
38.5
340
340 22
150 200
40
N° 2 Holes Ø 22
118,5
118.5
202 720
82
1004
172
28.5
360
28,5 360
28.5
28,5
417
417
E/0304/31A/22

Cut-outs for CVC 28 002yy - CVC 41 002yy
215
198 95
39
430 39
1234
6 x Ø8
530
240
390
400
215
201
40
113
36
Ø35
Ø22
103
59
390
508
59
E/0304/31A/23

8. Vibrations
The cooling unit does not produce any significant vibrations as the parts which generate
them are installed on anti-vibration devices.
9. Mechanical Parts
9.1 STRUCTURE
These machines are composed using self-supporting panels. These are made of passivated
and baked enamel sheet metal to guarantee resistance against corrosion*. They make the
machine easy to inspect and, at the same time, offer adequate protection to its internal
components.
Internal components of the structure are only accessible by removing cladding panels.
These are removed by extracting their fastening screws using suitable tools.
*suitable only to non-corrosive and non-salty environment
10. Cooling Components
These are connected together by copper piping, appropriately welded to ensure a good
seal.
10.1 REFRIGERANT
The refrigerant that is used: R134a (Tetrafluorethane).
It is neither toxic nor flammable and is not harmful to the ozone layer (ODP = 0).
10.2 COMPRESSOR
In this unit a reciprocating hermetic compressor is used.
Compressors are basically composed of an electric motor and a mechanical section which
is powered by this motor for pumping the refrigerant gas.
In reciprocating compressors the pumping unit consists of a piston which slides inside a
cylinder and which generates, depending on its phase, compression and aspiration.
10.3 CONDENSER
This part allows the release of the heat of the refrigerant gas in the environment. It consists
of an exchange pack with copper piping and aluminium fins.
(suitable only to non-corrosive and non-salty environment)
10.4 FILTER DRYER
This is a mixed mechanical/chemical filter and serves the purpose of filtering the refrigerant
which goes through it, at the same time eliminating humidity particles.
E/0304/31A/24

10.5 CAPILLARY PIPE EXPANSION SYSTEM
This part causes a pressure drop of the refrigerant before it comes into the evaporator.
10.6 EVAPORATOR
This is the part where the transfer of the heat, contained in the air in the cabinet, to the
refrigerant gas takes place .
It consists of copper pipes and aluminium fins.
(suitable only to non-corrosive and non-salty environment)
11. Motors
11.1 COMPRESSOR
Electric motor with a squirrel cage rotor, positioned inside the compressor and cooled by
the air flow. It is mounted on anti-vibration springs to reduce vibrations.
11.2 FANS
These may be of different types depending on the model. They are either:
- multiblade axial, with outside rotor on bearings, dynamically balanced;
- compact axial, on bearings;
- radial, with plastic or metal rotor, on bearings;
These fans are manufactured in accordance with Standard EN 60 335 1. They are treated
with anticorrosion plastic materials, with class B insulation and class 1 protection.
The motor protection is IP44, in accordance with Standard DIN40500 whereas the safety
rate complies with Standards DIN30110.
Noise levels are consistent with Standard DIN 45635.
E/0304/31A/25

12. Control, Monitoring and Safety Components
All equipment is set and inspected at the factory and generally does not require further
adjustments or interventions.
If, for specific reasons, it becomes necessary to perform modifications on the settings of
automatic devices this task must only be performed, subsequent to notification to the STULZ
engineering service, by specialized product expert.
STULZ air conditioner are equipped with a set of devices designed to ensure proper
operation. Intervention by any one of these automatic safety devices is a sign of a malfunction
and it is absolutely necessary to eliminate the cause of the malfunction.
WARNING!
It is prohibited to make electrical by-passes on safety equipment.
This intervention, in addition to being dangerous, also immediately invalidates
guarantee coverage for the product.
Interrupt electrical power to the unit before performing any repair or maintenance.
Work on the unit must only be done by expert, qualified and authorized personnel.
12.1 HIGH PRESSURE SAFETY SWITCH
stops compressor operation when the pressure inside the refrigeration circuit exceeds the
design values.
12.2 LOW PRESSURE SAFETY SWITCH
stops compressor operation when the pressure inside the refrigeration circuit drops below
the design values.
12.3 CONDENSATION CONTROL PRESSURE SWITCH
(fan speed control )
It controls the condenser fan speed to keep the condensing temperature constant.
Changes of fan speed are obtained by changing the supply voltage depending on the
condenser temperature.
12.4 CONTACTORS
control the motors by operating with auxiliary voltage.
They refer to IEC947-4-1 standards.
12.5 TRANSFORMER
refers to EN60742 standard and transforms the supply voltage to the auxiliary control voltage
E/0304/31A/26

12.6 REGULATING THERMOSTAT
The mechanical thermostat with a gas charge is positionned at the air intake of the cabinet
and it measures and controls the temperature to provide the start signal for the compressor.
It can be adjusted within the allowed temperature range of the technical data sheet.
12.7 HEATING ELEMENT THERMOSTAT (supplied with the reheat option, only for CVC14/
20/28/41)
The mechanical thermostat with a gas charge is positionned at the air intake of the cabinet
and it measures and controls the temperature to provide the start signal for the heating
element.
E/0304/31A/27

13. Electrical Connections
WARNING!
It is absolutely necessary, before making any connections, to use a suitable tester
to check the supply voltage. This must be the same as the voltage indicated on
the technical data plate.
The user must furnish and install, upstream from the unit, an isolating switch
with a pre-fuse and capacity as specified on the technical plate in order to be
able to perform maintenance on the unit in the absence of electricity.
• Check the supply voltage and frequency;
• Check that supply voltage and frequency are compatible with those for the unit.
• Interrupt both main power and auxiliary power before working on the system;
• Select connection cables (not supplied) according to EN60204-1 Standards
• On the main power supply lines, in preference install an omni-pole automatic switch,
curve type C, eventually complete of another differential switch. Alternatively, besides
the isolating omni-pole switch, install a safety fuse, retarded, aM type;
• Check that power cables are installed with a sufficient distance from alarm cables.
• Check that the supply voltage of the cooling unit is disconnected when opening the
cabinet doors.
• To connect power supply, use cables with section suitable to the power absorbed by the
users. These cables must be compliant with current standards.
ATTENTION!
The inobservance of these instructions might provoke damages or malfunction of
components and the warranty shall become forthwith void.
E/0304/31A/28

14. Start-up
Supply voltage to the cooling unit.
If the temperature in the room is lower than the temperature set on the thermostat the
evaporator fan will start and will cause air recirculation in the cabinet.
If the temperature in the room is higher than the temperature set on the thermostat then the
compressor and the condenser fan will start. They will operate until the temperature in the
room falls below the value set on the thermostat.
Note!
Avoid sudden stops and re-starts. At least 3 minutes should elapse between a stop and the
next re-start.
15. Adjusting the Temperature
Note!
Excessively low cabinet temperatures may cause serious problems to the cabinet parts
and require an increased power consumption for a higher cooling capacity.
Mechanical Thermostat
Adjustment
The adjustment should be made by experienced
personnel by acting on the thermostat pin with a
screwdriver after having switched off the voltage
and having removed the unit's front panel.
The thermostat has a 4°C hysteresis, therefore
the compressor will start at a temperature, which
is 4 Kelvin above the stop point. After the
adjustment replace the front panel and re-supply
voltage.
Adjustment screw
E/0304/31A/29

16. First Checks after Starting the Unit
Check that the air being released from the condenser into the environment flows correctly
without being drawn into the cooling unit.
Check that the evaporator fan functions properly.
Check, with the unit running, that the supply voltage remains within the values indicated
on the technical data plate
17. Switching off the Unit
To switch off the unit, disconnect the supply voltage from the system .
18. Maintenance
Very little ordinary maintenance is necessary, in view of the reliability and total automation
of moving parts. This maintenance, however, must be performed according to prescribed
maintenance intervals. Failure to perform maintenance, in addition to affecting the unit
durability and operation, invalidates the warranty.
WARNING!
Switch off the power supply of the unit before performing any maintenance
measures.
18.1 PREVENTIVE MAINTENANCE SCHEDULE
Two monthly
Check that the unit's condensate drainage system is perfectly clear and operational.
Yearly
Check that the fans do not show signs of overheating or abnormal vibrations.
Check that the exchangers are efficient and not soiled.
Note: If the air conditioner works in exceptionally dirty environments or if experience shows
that it requires more frequent maintenance then this maintenance must be performed as
required.
Note: After each scheduled and unscheduled service:
check that the condensate drainage system is perfectly efficient.
18.2 EXTRAORDINARY MAINTENANCE INTERVALS
Every 3 years or every 10,000 operating hours the unit must undergo a general overhaul
either at the manufacturer's factory or at companies authorized by STULZ or by qualified
agencies at the customer's own expense.
E/0304/31A/30

18.3 REPLACEMENT OF PARTS
To guarantee continuity of service to the units, it is recommended to replace some
components according to their MTBF (medium time before failure).
You can find the MTBF of the most critical components in the following table:
COMPRESSOR:
CONDENSER FAN:
EVAPORATOR FAN:
MECHANICAL THERMOSTAT:
COMPRESSOR RELAY:
30,000 operating hours
35,000 operating hours
40,000 operating hours
100,000 cycles
200,000 cycles
NOTE: the MTBFs in the table above are referred to the time during which the components
are operating. The ratio between this time and the total time of service depends on the type
of application, except for the evaporator fan (operating time is 100% of total service time).
Example:
If you esteem that the compressor will be operating 60% of the total time, the MTBF will be
30,000 working hours / 0.6 = 50,000 hours.
18.4 HOW TO CLEAN THE UNIT
Do not use acid or caustic substances to clean any part of the air conditioner.
The inner parts of the cooling unit, either on the room or cabinet side, must be cleaned with
a liquid detergent and compressed air having a pressure not higher than 4 bar, with the
unit properly earthed.
To clean the condenser remove the front panel and rinse with compressed air opposite to
the normal air flow direction through the heat exchanger.
19. Inactivity
If the unit remains inactive for longer periods of time, it is necessary to drain any condensate
residue and carry out a general cleaning procedure.
E/0304/31A/31

20. Options
20.1 ELECTRICAL REHEAT (only for CVC14/20/28/41) - RSC
is supplied when a warming of room air is required.
The heating control can be incorporated in the unit by a thermostatic device, possibly with
a contactor; or directly from the outside of the cooling unit by the customer's system.
The heating element is positioned protruding from the cooling unit in front of the air outlet.
Heating element
20.2 EMERGENCY VENTILATION EVAPORATOR FAN - EVDC24/EVDC48
With this option, evaporator fan is supplied with 24 or 48 VDC. DC evaporator fan must be
directly fed by the back-up battery, which is part of power supply system provided by the
client. DC emergency fans are not provided with a free-cooling system. Therefore, in case
of power supply shortage, they are useful only to recirculate air inside the cabinet.
20.3 PROTECTIVE TREATMENT ON CONDENSER COIL - PCC
Epoxy treatment on condenser coil surfaces to protect it against corrosion. This treatment
reduces condenser coil efficiency. Therefore, also cooling capacity of the unit is reduced.
E/0304/31A/32

20.4 ALUMINIUM CASING - CVCAL
With this option, casing of the unit is made of aluminium instead of standard steel zinc
plated sheet. As standard, aluminium casing is not painted.
20.5 HIGH/LOW TEMPERATURE ALARM THERMOSTAT - TMC/TMF
TMC (option for high temperature signal) and TMF (option for low temperature signal) are
mechanical wall-mounted thermostats. They consist of thermostats with bi-metallic sensor
element for switching signal transmitters. Their adjustable range is from 0°C to 60°C, contacts
6A-250VAC. Type of contacts NC for TMC and NO for TMF.
20.6 RELAY FOR POTENTIAL FREE COMMON ALARM SIGNAL (HIGH AND LOW
PRESSURE, HIGH TEMPERATURE) - CA
HP (high pressure alarm), LP (low pressure alarm) are not available as separate signals.
CA, common alarm, is the consequence of the following alarms (high pressure+low
pressure+high temperature). When one of these three symptoms appears, common alarm
is activated to warn about possible faults on the unit.
20.7 AIRFLOW SIGNAL - FL
It consists of a differential air pressure switch. It provides a voltage-free signal by a N.O.
contact when air flow pressure is different from the rated value, to indicate a fan malfunction.
This value of intervention is factory pre-set according to the unit model.
1 2
M1/14
3
M1/15
FL
E/0304/31A/33

21. Residual Hazards and Emergency Information
This unit was designed to reduce danger sources or situations to a minimum.
These dangers arise from improper use of the product or from failure to comply with
installation and operating instructions.
All personnel who work on or near the unit must be familiar with these instructions.
21.1 GENERAL SAFETY PROVISIONS
All personnel charged with testing and maintaining the unit must be familiar with the following
safety regulations:
· Danger signs must be easily visible in areas of potential danger.
· A visual supervision service must be set up in danger areas.
· Supervisors must keep constant contact with controllers.
· Transit zones, doors and ladders placed near the area where the unit is located must
never be blocked.
· Emergency exits must never be blocked.
· Slippery areas that could be a potential risk for persons must be covered with anti-slip
materials.
· Proper tools and suitable procedures must be used for every specific activity.
· Test tools and equipment must be kept in good order.
· Personnel must have in-depth knowledge of methods and procedures to apply in case of
fire (set up a fire extinguisher service in a handy position).
· The following actions must be taken if a fire starts:
- Switch off the electrical power supply to the component that is burning.
- Switch off all fans so as to cut the oxygene supply.
- Advise the appropriate department.
21.2 HAZARDS ARISING FROM THE PRODUCT COMING INTO CONTACT WITH
THINGS OR PERSONS
· Danger point 1a) comes from movement by the fan. The grating mesh has a useful gap,
between wires, smaller than 10 mm. Particles with smaller dimensions could be ejected
by the fan blade.
· Danger point 1b) comes from accidental contact with the heat exchanger since its
aluminium fins can have sharp edges.
21.3 HAZARDS ARISING FROM ELECTRICAL FAULTS
21.3.1 SAFETY STANDARDS FOR ELECTRICAL EQUIPMENT
Introduction
The causes of electrical risks are well known and it is not difficult to prevent these risks by
applying constant care and attention.
Assigned personnel must be informed regarding potential dangers and trained regarding
safety procedures in order to reduce the number of potential electrical accidents.
E/0304/31A/34

21.3.2 TASKS ASSIGNED TO PLANT MANAGERS
Plant managers must be informed regarding potential risks in the system and must
superintend personnel that works with electrical equipment.
Superintending tasks consist of localizing possible risk situations and investigating
problems encountered by personnel when performing maintenance.
Each defective component must be immediately repaired or replaced.
The manager must insist on application of safety measures. He must not tolerate or accept
deviations from these because this could cause harm to persons or to the machinery.
21.3.3 HIGH VOLTAGE
Contact with high voltage circuits can cause burns, shock, unconsciousness or even death
for the persons involved.
This problem can be caused by poor understanding of the dangers inherent to use of
electrical devices.
Damage to the human body, in this case, depends on the intensity of current, the duration
of current and the path the current takes as it goes through the body.
21.3.4 SAFETY STANDARDS TO COMPLY WITH WHEN THE EQUIPMENT IS
SWITCHED OFF
Interrupt the power supply to the unit before opening it.
Make sure no electricity is present in the unit's circuits.
Clean and dry the work area.
Remove dowels, rings, brackets or metal parts which can hamper the job to be done or
become potential conductors for electricity.
Ground or short-circuit the terminals of the fan capacitors in the de-energized circuit.
Remove fuses only after the circuit has been deactivated.
21.3.5 SAFETY STANDARDS TO COMPLY WITH WHEN PERFORMING MAINTENANCE
ON LIVE
The following standards must be complied with, in addition to those stated at point 2.3.4
above:
· personnel must never work alone;
· work should be done, if possible, using only one hand;
· use only authorized procedures to perform by-passes at interlocks;
· make sure assigned personnel are perfectly familiar with the machine's components and
maintenance procedures before starting to work;
· use protective gloves;
· open all contacts that bring power to the equipment before measuring resistance values;
· check that there is no high voltage in the low voltage circuits;
· do not use magnetic tools near strong magnetic fields.
21.3.6 SAFETY STANDARDS TO COMPLY WITH DURING MAINTENANCE
If continuous operation is not required, the system must be turned off.
E/0304/31A/35

Before beginning work, the following is required:
· check the maintenance person and make sure he is not carrying objects which could
become conductors;
· inspect the work site and make sure the floor is clean an dry;
· inspect work tools. These must be suited for the job to be done and be in good condition
in order to permit safe maintenance;
· measuring instruments must be periodically calibrated;
· check work procedures before starting the job. Check the wiring diagram and get an
overall picture of how the system is structured.
It is necessary, while maintenance is being done:
· for the maintenance person to be aware of which circuits are under high voltage;
· no resistance measurements must be made on live circuits;
· use only one hand when testing live circuits;
· ground the terminals of the instrument before measuring live circuits;
· always strictly comply with the suggestions mentionned above
Maintenance can be held to be terminated when all components have been reinstalled
and the unit has its original appearance.
21.4 SAFETY STANDARDS TO COMPLY WITH WHEN WORKING ON REFRIGERATION
CIRCUITS
The refrigerant used for this machine can be dangerous if it is not properly used. Several
precautions must be taken when handling this substance:
· never release, store or use the refrigerant near open flames. The refrigerant is non-toxic.
Contact with flames causes combustion which generates toxic gases that can corrode
metal surfaces;
· never expose the eyes to contact with the refrigerant since it can reach temperatures of
-40°C;
· never expose the skin to contact with the refrigerant. If this happens then the damaged
part must be treated using the same procedures used in combination with frostbite and
freezing;
· avoid high concentrations of refrigerant since these can cause suffocation. In this case
the person must be evacuated from the room and undergo artificial respiration;
· avoid brazing or welding in the presence of refrigerant vapours;
· do not place gas heating equipment or electrical radiators in places where refrigerant
vapours may be present;
· do not smoke;
· do not overheat gas cylinders; do not exceed the refrigerant gas limit indicated on the
technical data plate;
· the cooling system must be handled with care as it may contain acids as a result of motor
burn-out.
Therefore, protective gloves, goggles and clothing must be worn.
E/0304/31A/36

· eliminate pressure from the entire cooling system before brazing or welding. Welding
when the circuit is under pressure is extremely dangerous due to the risk of the piping
rupturing and molten material being projected by the refrigerant gas pressure.
21.5 HAZARDS ARISING IN CASE OF FIRE
There are no direct dangers.
The refrigerant gas, in the presence of flames, generates toxic and corrosive substances.
The way to prevent this risk, in view of the relatively small quantities of refrigerant contained
in the machine, is to position the unit in adequately ventilated rooms.
21.6 TOXIC SUBSTANCES
The gas contained and used in this product is an ecological type of gas. A very small
quantity is used and the circuit is hermetically sealed.
All leaks with a loss of more than 15 grams per year are checked and eliminated during
testing.
The producer of the refrigerant gas states that gas concentrations inferior to 1 to 1000 are
non toxic. When the machine is not installed in a well-ventilated or suitably large room and
there is a substantial leak of refrigerant then the room should be ventilated and personnel
should be sent out from the room.
21.7 HAZARDOUS FLUIDS
The unit does not contain any fluids which are hazardous to people.
During operation, the A/C unit produces condensate which is drained into the environment
if it is not dissipated by the dissipator. It is recommended to drain this fluid adequately by
condensate lines so as to prevent possible hazards to people in the area.
E/0304/31A/37

22. Disassembling the Unit
WARNING!
This unit contains refrigerant gas and a small quantity of lubricants (esters) in the
compressor. These components are pollutants for the environment and must not
be dispersed.
Disassembling operations on this unit must only be done by experts
Before starting to dismantle the unit check that it has been disconnected from
electric mains.
This unit must be disassembled by authorised organisations.
STULZ is able and has equipment for disposing of these units and performing almost total
recuperation of components without harm to the environment.
While awaiting disposal the unit must be kept stored protected from weather.
E/0304/31A/38

23. Faults, Probable Causes, Possible Remedies
23.1 FAILS TO COOL
.1 No part is working;
.1 Lack of voltage to the unit;
.1 Check that doors closed and switches are turned on.
.2 Compressor, condenser fan and evaporator fan not working;
.1 Cooling system has run out of refrigerant;
.1 Contact STULZ technician or service department;
.2 Compressor mechanically defective;
.1 Contact STULZ technician or service department.
.3 Compressor and condenser fan working, evaporator fan not working;
.1 fan capacitor is defective;
.1 Replace fan capacitor;
.2 Evaporator fan defective;
.1 Replace fan.
.4 Condenser and evaporator fan working, compressor not working;
.1 Where present, compressor circuit breaker defective;
.1 Replace circuit breaker and check efficiency of the compressor's
electrical parts;
.2 Compressor start relay defective;
.1 Replace compressor start relay;
.3 Where present, start-up condenser defective;
.1 Replace start-up condenser;
.4 Compressor motor defective;
.1 Contact STULZ refrigerant system technician or service department.
.5 High pressure switch defective;
.1 Contact STULZ refrigerant system technician or service department;
.6 Where present, compressor remote control switch defective
.1 Replace remote control switch.
.5 Evaporator and condenser fan and compressor working;
.1 Adjustment thermostat defective or calibrated at a temperature exceeding
the temperature in the cabinet;
.2 When present, anti-freeze thermostat defective.
23.2 FAILS TO COOL SUFFICIENTLY
.1 Evaporator fan working, compressor and condenser fan working
intermittently
.1 Service anti-freeze thermostat;
.1 Clean evaporator
.2 Check for any external causes which may limit the airflow to the
inside circuit;
.2 Where present, service low pressure switch;
E/0304/31A/39

.1 Insufficient charge in the refrigerant circuit;
Contact STULZ refrigerant system technician or service department;
.3 Where present, solenoid valve defective;
.1 Replace solenoid valve coil;
.2 Contact STULZ refrigerant system technician or service department;
.2 Condenser fan, evaporator fan working, compressor working
intermittently;
.1 Where present, service high pressure switch;
.1 Room temperature exceeding maximum temperature as shown on
technical data plate;
.1 Ventilate room;
.2 Contact STULZ service department;
.2 Dirty air filter,
.1 Clean or, if necessary, replace dirty air filter;
.3 Dirty condenser;
.1 Clean condenser;
.4 Air short-circuit,
.1 Check that no obstruction or obstacle are causing the expelled
air to short circuit;
.2 Check that requirements concerning minimum distance from a
wall, from the ceiling, from the electric cabinet or from any other air
cooling unit are as described in this manual;
.2 Service compressor heat protector,
.1 Air temperature in cabinet exceeding maximum temperature shown
on unit's technical dataplate;
.2 Same causes and relevant remedies as outlined under items
22.2.2.1.1/2/3/4;
.3 Evaporator fan working, condenser fan not working, compressor working
intermittently;
.1 fan capacitor is defective;
.1 Replace fan capacitor:
.2 Condenser fan defective;
.1 Replace condenser fan:
23.3 EXCESSIVE CONDENSATE FORMATION;
.1 Cabinet with protection level lower than IP54;
.1 Check that the self-adhesive seal between the cooling unit and the cabinet
has been correctly applied;
.2 Check that the unit's locking panels have been correctly installed;
.3 Check that there are no openings in the cabinets.
E/0304/31A/40