Cetetherm Micro Manual

DOC1355, 16-03-2021
Installation, service and operating instruction Cetetherm Micro
Heating & domestic hot water substation for apartments and single family houses

This manual is published by Cetetherm.
Cetetherm can without further notice make changes and improvements to the content in this manual if it is necessary due to printing
mistakes, wrong information or changes in the hardware or software.
All these types of changes will be included in future release of the manual.

Cetetherm Micro
Installation, service and operating instruction
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Contents
1General information................................................................................................................ 6
Comfort......................................................................................................................................................6
Installation .................................................................................................................................................6
Long-term security.....................................................................................................................................6
CE-marking................................................................................................................................................6
General warnings ......................................................................................................................................7
Micro STC and Micro STC2 warnings.......................................................................................................7
2Operating instructions ........................................................................................................... 8
General operation......................................................................................................................................8
Heating operation Micro STC and Micro STC2.........................................................................................8
Heating operation Micro RTC....................................................................................................................8
Safety equipment/inspection .....................................................................................................................8
3Product overview.................................................................................................................... 9
Product overview AquaMicro.....................................................................................................................9
Product overview Micro DPC ..................................................................................................................10
Product overview Micro RTC...................................................................................................................11
Product overview Micro STC...................................................................................................................12
Product overview Micro STC2.................................................................................................................13
Product overview Micro HTC...................................................................................................................14
Symbols on the first fix-jig .......................................................................................................................14
4Installation............................................................................................................................. 15
Unpacking................................................................................................................................................15
Preparation..............................................................................................................................................15
Mounting..................................................................................................................................................15
Mounting options general ........................................................................................................................16
Mounting options Micro STC and Micro STC2...................................................................................16
Adjustments and settings general ...........................................................................................................16
Adjustments and settings With a Micro HTC: ....................................................................................16
Commissioning advice Micro STC and Micro STC2 ...............................................................................17
Dismantlement.........................................................................................................................................17
User instruction HTC hot water actuator .................................................................................................17
Installing the room thermostat Round .....................................................................................................18
Installing the control panel CM737..........................................................................................................19
Installing the outdoor temperature sensor...............................................................................................21
Starting up sequence with component check..........................................................................................21
5CM737- settings to be done after start-up.......................................................................... 22
Configure the control panel after installation...........................................................................................22
Setting the day ........................................................................................................................................22
Setting the time .......................................................................................................................................22
6Room thermostat Round...................................................................................................... 23
General....................................................................................................................................................23
Control modes .........................................................................................................................................24
Changing control mode, OTC heating curve and max supply temperature............................................24
OTC control mode, default setting ..........................................................................................................25
Viewing the room temperature ................................................................................................................25
Viewing the set room temperature ..........................................................................................................25
Changing temperature setting.................................................................................................................25
Setback....................................................................................................................................................25
Summer heating ......................................................................................................................................25
Display symbols ......................................................................................................................................26
Fault messages on the room thermostat.................................................................................................27
Fault codes on room thermostat Round..................................................................................................27
Factory settings, room thermostat...........................................................................................................28
7Connect the Round to internet via Gateway ...................................................................... 29
Set-up account and download the app....................................................................................................29

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Installation, service and operating instruction
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Troubleshooting.......................................................................................................................................30
Clearing binding between Round and the Gateway................................................................................31
8Installing the room thermostat CM737 ............................................................................... 32
General....................................................................................................................................................32
Choosing the operating mode .................................................................................................................33
Temperature Enquiry with the Info-button (7) .........................................................................................33
Holiday function.......................................................................................................................................34
OTC heating curve ..................................................................................................................................34
Parallel adjustment of heating curve .......................................................................................................34
Operating mode Auto ..............................................................................................................................35
The Built-in Heating Program.............................................................................................................35
Reviewing the Heating Program ........................................................................................................35
Temperature Override........................................................................................................................35
Disabling/enabling time periods .........................................................................................................35
Modifying the heating program...........................................................................................................36
9Activation of installer parameters CM737 .......................................................................... 37
Entering the installer set-up mode ..........................................................................................................37
CM737–Category 1: Control panel settings ............................................................................................38
CM737-Category 2: ECO-functions ........................................................................................................38
CM737-Category 3: Setting and displaying sensor values .....................................................................39
CM737-Category 4: Heating actuator settings........................................................................................39
CM737-Category 5: Fault History............................................................................................................39
10 Troubleshooting the CM737 ................................................................................................ 40
Fault Codes on the CM737 .....................................................................................................................41
11 Differential pressure control valve, DPC ............................................................................ 42
Setting the DPC valve .............................................................................................................................42
Flow rate graph of the DPC.....................................................................................................................42
12 Pump settings and pump performance .............................................................................. 43
Grundfos Alpha2L settings ......................................................................................................................43
Pump curve .............................................................................................................................................44
13 Electrical circuit diagram ..................................................................................................... 45
Micro RTC ...............................................................................................................................................45
Micro STC and Micro STC2 ....................................................................................................................46
14 Service instructions ............................................................................................................. 47
General service instructions ....................................................................................................................47
Tap water temperature too low ..........................................................................................................47
Tap water temperature too high.........................................................................................................47
Hot water temperature unstable or too low ........................................................................................48
Heating system temperature too high or too low ...............................................................................48
No heating ..........................................................................................................................................48
Heating temperature unstable............................................................................................................48
STC service instructions..........................................................................................................................49
Heating system temperature too high or too low ...............................................................................49
No heating ..........................................................................................................................................49
Disturbing noise from the circulation pump/ Noise in the radiator system.........................................50
Heating temperature unstable............................................................................................................50
HTC service instructions .........................................................................................................................50
Tap water temperature too low/ hot water temperature unstable or too low......................................50
Heating system temperature too high or too low ...............................................................................50
15 Service actions for the installer .......................................................................................... 51
Check the function of the valve for hot water..........................................................................................51
Check the function of the heating actuator and valve .............................................................................52
Run the pump manually ..........................................................................................................................52
16 Maintenance and repairs...................................................................................................... 53
Cleaning the heating media filter.............................................................................................................53
Change the hot water actuator and heat exchanger...............................................................................54
Change the hot water valve.....................................................................................................................54

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Installation, service and operating instruction
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Change the heating actuator...................................................................................................................55
Change the heating valve........................................................................................................................55
Change pump components or the complete pump .................................................................................56
Change the heating circuit supply temperature sensor...........................................................................56
Change the outdoor temperature sensor ................................................................................................56
Change the differential pressure control valve........................................................................................57
Change the flow switch ...........................................................................................................................57
17 Operating data and performance ........................................................................................ 58
Operating data.........................................................................................................................................58
AquaMicro ..........................................................................................................................................58
Micro DPC, Micro RTC, Micro HTC, Micro STC, Micro STC2 ...........................................................58
Technical Data ........................................................................................................................................59
Measure sketch .......................................................................................................................................60
18 Options .................................................................................................................................. 61
Safety thermostat ....................................................................................................................................61
Installing the safety thermostat................................................................................................................61
Parameters and recommended settings for under floor heating........................................................61
First fix-jig ................................................................................................................................................62

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Installation, service and operating instruction
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1 General information
Cetetherm Micro is a complete, ready-to-install heating network substation for hot water and heating. It is
designed for buildings with a connection to a heating network. Cetetherm has years of experience in heating
network technology and has developed Cetetherm Micro with well-planned pipe work and with all components
easily accessible for inspection and possible future servicing.
Comfort
Cetetherm Micro has fully-automatic temperature control for heating and hot water. The hot water is controlled
and maintained at the desired temperature. The heating is controlled in relation to desired room temperature.
Installation
Compact dimensions, light weight, well arranged plumbing and factory-complete internal wiring – all make
installation very simple. A pre-programmed control unit and a power cable already fitted with a plug make
things even simpler to allow immediate start-up.
Micro is designed for hanging on wall and is mounted on an insulated frame and includes an insulated cover.
Better insulation means less energy usage and better energy efficiency.
Long-term security
The heat exchanger plates and all piping are manufactured in acid-resistant stainless steel. All components are
closely matched and carefully tested for function in accordance with quality assurance system ISO9001:2015
For future servicing requirements, all components are easily accessible and individually replaceable.
CE-marking
Cetetherm Micro follows the rules and legislation specified in the Declaration of Conformity.
To maintain the validity of the CE marking, only identical replacement parts must be used.

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Installation, service and operating instruction
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General warnings
The installation work must be carried out by an authorized installation contractor. Before the
system is taken into operation, it must be pressure tested in accordance with relevant
regulations.
The temperature and the pressure of the primary heating water are very high. Only qualified
technicians can work with the substation. Incorrect operation may cause serious personal
injury and result in damage to the building.
If the hot water temperature is set too high, people may be scalded. If the hot water
temperature is set too low, unwanted bacteriological growth may occur in the hot water system.
This can result in serious personal injury.
Parts of the substation may get very hot and should not be touched.
When starting up the substation: To avoid the risk of scalding, make sure that no-one draws
any hot water until the hot water temperature has been adjusted.
Start heating circulation by first opening the valves in the primary heating supply and then
return lines, to avoid pollutions in the system. Open the valves slowly to avoid pressure surges.
Micro STC and Micro STC2 warnings
Before the substation is connected to the electrical supply, make sure that the heating system
is topped up with water. Starting up the system without water will damage the circulation pump.
The substation comes prepared with an electrical plug to be connected to the main supply. The
strain relief clips of the cable must be fitted so that there is no risk of damage. If necessary, the
plug-and-socket connection can be replaced with a permanent installation with an all-pole
isolate switch. This must be carried out by a qualified electrician.
Do not shut of the electrical supply to the room thermostat, this will damage the circulation
pump, valves, actuators etc.

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Installation, service and operating instruction
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2 Operating instructions
General operation
The temperature and pressure of the incoming heating network water are very high. The heat from the heating
network water is transferred to the heating and hot water systems of the building in the heat exchangers. The
heat is transferred through thin plates of acid-resistant stainless steel which keep the heating network water
separate from the systems in the building.
Micro has automatic temperature control for hot water. This measures the temperature of the hot water in the
heat exchanger and automatically controls the primary flow.
The hot water temperature is controlled by a temperature control system which is set to about 50 ºC.
If the temperature is set too high, there is a risk of scalding. Setting the hot water temperature too low may
result in unwanted bacteriological growth in the hot water system.
After adjustment, the Micro operates completely automatically. However, in hard water areas it is advisable to
be attentive and to remedy any faults in good time if the temperature of the hot water is too high; otherwise the
risk of lime deposits in the heat exchanger may increase.
The energy supplier registers the use of energy. Measurement is done by recording the flow of heating network
medium through the system, and by measuring the temperature difference between the medium’s supply and
return flow.
Heating operation Micro STC and Micro STC2
With a Micro STC or a Micro STC 2, the heating circuit is controlled in relation to outdoor temperature (option)
and/or desired room temperature by means of a room thermostat and temperature sensor. When no heat is
needed, the circulation pump in the heating circuit stops automatically, but is started regularly to make sure that
it does not seize up during long idle periods.
Micro STC2 has an extra heating connection that can be connected to radiators or towel heating.
Heating operation Micro RTC
With a Micro RTC, the heating circuit is controlled with a desired room temperature by means of a room
thermostat. When the measured room temperature is to low according to desired room temperature, the relay
box sends a signal to open the relay.
Safety equipment/inspection
•Daily inspection to check for leaks from pipes or components.
•Weekly inspection to make sure that the operation of the heating and hot water control systems is
stable and that the temperature does not fluctuate. Temperature hunting causes unnecessary wear of
valves, thermostats and heat exchangers.
•Every three months check the safety valves and the pressure in the heating system.
To check the operation of a safety valve, turn its wheel/knob until water escapes from the waste pipe of the
valve, then close the wheel/knob quickly. Occasionally a safety valve may open automatically to release excess
pressure. After a safety valve, has been open it is important that it closes properly and does not drip.

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Installation, service and operating instruction
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3 Product overview
Note: The product overview pictures are shown without the insulation.
Product overview AquaMicro
Picture 1
1
Heat exchanger and temperature
controller for hot water
9
Adapter for Hot water flow meter
2
Control valve for hot water
10
Heating network media, supply
3
Temperature sensor connection,
heating media supply
11
Heating network media, return
4
Filter for heating media
12
Cold water (cw)
5
Adapter for energy meter
13
Cold water outlet (cw)
6
Check valve for cold water
14
Hot water (hw)
7
Adapter for Cold water flow meter
30
First fix jig including shut-off valves (option)
8
Safety valve for domestic hot water

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Installation, service and operating instruction
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Product overview Micro DPC
Picture 2
1
Heat exchanger and temperature
controller for hot water
10
Heating network media, supply
2
Control valve for hot water
11
Heating network media, return
3
Temperature sensor connection,
heating media supply
12
Cold water (cw)
4
Filter for heating media
13
Cold water outlet (cw)
5
Adapter for energy meter
14
Hot water (hw)
6
Check valve for cold water
15
Differential pressure controller
7
Adapter for Cold water flow meter
16
Heating circuit, return
8
Safety valve for domestic hot water *)
17
Heating circuit, supply
9
Adapter for Hot water flow meter
30
First fix jig including shut-off valves (option)
*) included depending on model

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Installation, service and operating instruction
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Product overview Micro RTC
Picture 3
1
Heat exchanger and temperature
controller for hot water
13
Cold water outlet (cw)
2
Control valve for hot water
14
Hot water (hw)
3
Temperature sensor connection,
heating media supply
15
Differential pressure controller
4
Filter for heating media
16
Heating circuit, return
5
Adapter for energy meter
17
Heating circuit, supply
6
Check valve for cold water
18
Flow switch for domestic hot water *)
7
Adapter for Cold water flow meter
19
Control valve, heating circuit
8
Safety valve for domestic hot water *)
20
Actuator, heating circuit
9
Adapter for Hot water flow meter
21
Connection box for electric power and sensors,
heating circuit
10
Heating network media, supply
22
Room thermostat/control panel *)
11
Heating network media, return
30
First fix jig including shut-off valves (option)
12
Cold water (cw)
*) included depending on model

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Installation, service and operating instruction
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Product overview Micro STC
Picture 4
1
Heat exchanger and temperature
controller for hot water
15
Differential pressure controller *)
2
Control valve for hot water
16
Heating circuit, return
3
Temperature sensor connection,
heating media supply
17
Heating circuit, supply
4
Filter for heating media
18
Flow switch for domestic hot water *)
5
Adapter for energy meter
19
Control valve, heating circuit
6
Check valve for cold water
20
Actuator, heating circuit
7
Adapter for Cold water flow meter
21
Connection box for electric power and
sensors, heating circuit
8
Safety valve for domestic hot water *)
22
Room thermostat/control panel
9
Adapter for Hot water flow meter
23
Outdoor temperature sensor *)
10
Heating network media, supply
25
Circulation pump, heating circuit
11
Heating network media, return
26
Safety thermostat (option)
12
Cold water (cw)
27
Supply temperature sensor, heating circuit
13
Cold water outlet (cw)
30
First fix jig including shut-off valves (option)
14
Hot water (hw)
*) included depending on model

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Installation, service and operating instruction
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Product overview Micro STC2
Picture 5
1
Heat exchanger and temperature
controller for hot water
15
Differential pressure controller *)
2
Control valve for hot water
16
Heating circuit, return
3
Temperature sensor connection,
heating media supply
17
Heating circuit, supply
4
Filter for heating media
19
Control valve, heating circuit
5
Adapter for energy meter
20
Actuator, heating circuit
6
Check valve for cold water
21
Connection box for electric power and sensors,
heating circuit
7
Adapter for Cold water flow meter
22
Room thermostat/control panel
8
Safety valve for domestic hot water *)
23
Outdoor temperature sensor
9
Adapter for Hot water flow meter
25
Circulation pump, heating circuit
10
Heating network media, supply
26
Safety thermostat (option)
11
Heating network media, return
27
Supply temperature sensor, heating circuit
12
Cold water (cw)
28
Heating circuit primary temp, return
13
Cold water outlet (cw)
29
Heating circuit primary temp, supply
14
Hot water (hw)
30
First fix jig including shut-off valves (option)
*) included depending on model

Cetetherm Micro
Installation, service and operating instruction
14
Product overview Micro HTC
Picture 6
1
Heat exchanger and temperature
controller for hot water
11
Heating network media, return
2
Control valve for hot water
12
Cold water (cw)
3
Temperature sensor connection,
heating media supply
13
Cold water outlet (cw)
4
Filter for heating media
14
Hot water (hw)
5
Adapter for energy meter
15
Differential pressure controller
6
Check valve for cold water
16
Heating circuit, return
7
Adapter for Cold water flow meter
17
Heating circuit, supply
8
Safety valve for domestic hot water
19
Control valve, heating circuit
9
Adapter for Hot water flow meter
20
Actuator, heating circuit
10
Heating network media, supply
30
First fix jig including shut-off valves (option)
Symbols on the first fix-jig
The first fix-jig has symbols that show which supply and return pipe that should connect to the different
connection points.
Picture 7
1
Heating circuit, return
2
Heating circuit, supply
3
Heating network media, supply
4
Heating network media, return
5
Hot water (hw)
6
Cold water outlet (cw)
7
Cold water (cw)

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Installation, service and operating instruction
15
4 Installation
Unpacking
•Remove the transport packaging and check that the product has not been damaged in transit and that
the consignment agrees with the specifications.
•When lifting the unit take care not to apply stress to pipes and heat exchanger as this may weaken
them. Avoid lifting the unit by holding the heat exchanger.
Note: Risk of injury lifting heavy objects.
Preparation
•Choose a suitable installation area in accordance with official regulations.
The system may generate sounds during operation caused by pumps, regulators systems, flows etc.
This should be taken in consideration during installation of the unit so that possible operational sounds
affect the surroundings as little as possible. This means that the system should be installed on well-
insulated walls, such as outer walls or on concrete walls.
•Check the applicable regulations of the primary heating supplier. The available differential pressure
should be for:
oAquaMicro: at least 50kPa and at most 600 kPa
oMicro DPC, RTC STC, STC2 and HTC at least 50 kPa and at most 400 kPa
Where the differential pressure is higher, a differential pressure controller should be added to the
installation.
•Flush out the heating and hot water systems.
•Mount the first fix-jig (option) to the connection points. Tighten with 45 Nm.
•Carefully loosen the electrical plug from the insulation and attached it to the correct power cable.
Make sure that the cable is fasten in the insulation
Picture 8
Mounting
•Mount the substation on the wall using four screws or bolts suitable for the material of the wall and for
the weight of the unit. The unit may be mounted at any height on the wall, but 1500 – 1800 mm from
floor to keyhole fixing may be taken as a guide. The hole pattern for screws/bolts and the piping
connection measures is shown in 17.3 Measure sketch.
•Drainage pipe from the safety valve must be taken to floor gully.
•Energy meters must be installed at a prepared location, replacing a gauge block, or following the
instructions of the energy supplier.
•Retighten all connections, including those made at the factory. Tighten with 45 Nm. If connections need
retightening after the installation has been taken into service, the system should be depressurised
before retightening. If the system is not depressurised before retightening, gaskets will be damaged.
•Connect the pipe work to the first fix-jig (option) connection points. Tighten with 45 Nm.

Cetetherm Micro
Installation, service and operating instruction
16
•Bleed the heating system.
Start the heating circulation pump with the highest output setting. Let the heating system heat up and
bleed the system again.
•Set the pump capacity of the heating circulation pump according to the pressure head diagram.
Use the lowest setting that manages the heating demand for best electrical efficiency.
Mounting options general
•If the substation is connected to a system sensitive to high temperature or to a low temperature
system, for example floor heating, a safety thermostat must be mounted and activated before start up.
See 18.1.
For more information; contact the supplier of the under-floor heating system.
Mounting options Micro STC and Micro STC2
•Install the room thermostat.
oRoom thermostat Round: see 4.9 Installing the room thermostat Round or
oRoom thermostat CM737: see 4.10 Installing the control panel CM737.
•Mount the outdoor temperature sensor (option) on the north side of the building, 2 metres above the
ground, or higher. See 4.11 Installing the outdoor temperature sensor
Adjustments and settings general
•Open up incoming cold water supply and fill the service water and heating circuits, bleeding off any
trapped air.
•Check the operation and opening pressures of the safety valve.
•Adjust the hot water temperature by having a hot water tap open at normal flow
rate for a time. Measure the temperature at the draw-off point with a thermometer.
It takes about 20 seconds to get stable tap water temperature
The temperature should be approximately 50°C, this corresponds to a set point of
approximately 1,5 on the actuator.
See chapter 14 Service instructions for adjusting hot water temperature.
Cetetherm recommends that the tap water temperature is set to 10º less than the
primary inlet temperature.
NOTE: Make sure that no cold water is mixed with the hot water while making this
adjustment.
Picture 9
•The property owner must be instructed in the operation, setting and care of the unit. It is particularly
important to provide information about the safety systems and about hazards that may arise in relation
to the high pressure and temperature of the primary heating water.
Adjustments and settings With a Micro HTC:
Recommended set point for the actuator is 5 or 6.
Set point
2
3
4
5
6
7
°C (approx.)
20
30
40
50
60
70
Cetetherm recommends that the tap water temperature is set to 15º less than the primary inlet temperature
with a Micro HTC
NOTE: Make sure that no cold water is mixed with the hot water while making this adjustment.
•The property owner must be instructed in the operation, setting and care of the unit. It is particularly
important to provide information about the safety systems and about hazards that may arise in relation
to the high pressure and temperature of the primary heating water.

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Installation, service and operating instruction
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Commissioning advice Micro STC and Micro STC2
•Set the control mode on the control panel.
Control panel Round has been pre-set at the factory to use control mode; Outside Temperature Control
(OTC control). To change control mode see 6 Room thermostat Round.
Control panel CM737 see 5 CM737- settings to be done after start-up.
The control panel has been pre-set at the factory to use Outdoor compensation
(parameter 14:rC set to 1 ). To change see 5.1 Configure the control panel after installation.
Dismantlement
When the time comes for the substation to be dismantled and scrapped it must be disposed of in the correct
manner in accordance with local or national regulations.
User instruction HTC hot water actuator
Hot water temperature in apartments or one family houses can be set to about 50°C. If the temperature is set
too high, there is a risk of scalding. Setting the hot water temperature too low may result in unwanted
bacteriological growth in the hot water system.

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Installation, service and operating instruction
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Installing the room thermostat Round
1 Removing power supply
2 Placement
3 Removing the dial
4 Removing the thermostat
5a Mounting direct on the wall
5b Mounting in wall socket
6 Connecting the cable
7 Mounting the thermostat
8 Mounting the dial
Picture 10

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Installation, service and operating instruction
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Installing the control panel CM737
The control panel CM737 can be used as a room thermostat.
Before installation make sure that the electrical power supply is disconnected.
Install the room thermostat at an appropriate location that is representative to the indoor temperature.
Picture 11
•A suitable installation is about 1.5 meters above floor and on an inner wall.
•The room thermostat must not be combined with other thermostats in the same control zone.
Use a suitable 2-conductor cable between the connection box and the operator control panel. With a conductor
area of 0.6 mm2, the maximum cable length is 50 metres. Maximum 5Ω/conductor. Install the cable ends in the
terminal, marked A and B, located in the operator control panel. Connect the plug to the connection box again.
The unit can now be connected to the electrical power.
After starting up, choose configuration and operating mode, see 5.1 Configure the control panel after
installation.

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Installation, service and operating instruction
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Picture 12