Cetetherm Mini Plus CM737 Manual

DOC-1272 Rev: 2018-06-01
Installation, service and operating instruction Cetetherm Mini Plus CM737 DHWC
och serviceinstruktion Mini/Mini XL RVS46
District heating substation for single-family houses and multi-family buildings (1 to 12 apartments)

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.
For additional online information and manual:
URL address:
http://www.alfalaval.com/mini-plus
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Cetetherm Mini Plus CM737
Installation, service and operating instruction
1
Contents
1General information..............................................................................................................3
1.1 Comfort......................................................................................................................................................3
1.2 Installation .................................................................................................................................................3
1.3 Long-term security.....................................................................................................................................3
1.4 CE-marking................................................................................................................................................3
1.5 Information about the document................................................................................................................3
1.6 General warnings ......................................................................................................................................4
2Operating instructions..........................................................................................................5
2.1 Operation...................................................................................................................................................5
2.2 Safety equipment/inspection .....................................................................................................................5
3Product overview..................................................................................................................6
4Installation.............................................................................................................................7
4.1 Unpacking..................................................................................................................................................7
4.2 Preparation................................................................................................................................................7
4.3 Mounting....................................................................................................................................................7
4.4 Mounting options.......................................................................................................................................8
4.5 Adjustments and settings ..........................................................................................................................8
4.6 Dismantlement...........................................................................................................................................8
4.7 Commissioning advice ..............................................................................................................................8
5Measure sketch Mini Plus ....................................................................................................9
6Control panel with room thermostat CM737 .....................................................................10
6.1 General................................................................................................................................................... 10
7Installing and start up the control panel ...........................................................................11
7.1 Using the control panel as a room thermostat ....................................................................................... 11
7.2 Installing the outdoor temperature sensor.............................................................................................. 13
7.3 Starting up and component control of control panel............................................................................... 13
7.4 Configure the control panel after installation.......................................................................................... 13
7.5 Setting the day........................................................................................................................................ 14
7.6 Setting the time....................................................................................................................................... 14
8Operating the room thermostat CM737.............................................................................15
8.1 Choosing the operating mode................................................................................................................ 15
8.2 Temperature Enquiry with the Info-button (7) ........................................................................................ 15
8.3 Holiday function...................................................................................................................................... 16
8.4 OTC heating curve ................................................................................................................................. 16
8.5 Parallel adjustment of heating curve...................................................................................................... 16
8.6 Operating mode Auto ............................................................................................................................. 17
8.6.1 The Built-in Heating Program............................................................................................................ 17
8.6.2 Reviewing the Heating Program ....................................................................................................... 17
8.6.3 Temperature Override....................................................................................................................... 17
8.6.4 Disabling/enabling time periods ........................................................................................................ 17
8.6.5 Modifying the heating program.......................................................................................................... 18
9Activation of installer parameters......................................................................................19
9.1 Entering the installer set-up mode ......................................................................................................... 19
9.2 Category 1 parameters: Control panel settings...................................................................................... 20
9.3 Category 2 parameters: ECO-functions................................................................................................. 20
9.4 Category 3 parameters: Setting and displaying sensor values.............................................................. 21
9.5 Category 4 parameters: Heating actuator settings................................................................................. 21
9.6 Category 5: Fault History........................................................................................................................ 21
10 Troubleshooting the control panel....................................................................................22
10.1 Fault codes on the control panel............................................................................................................ 23
11 Electrical circuit diagram ...................................................................................................24
12 Schematic diagram, main components.............................................................................25
13 Pump settings and pump performance.............................................................................26
13.1 General................................................................................................................................................... 26

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13.2 DHWC-pump Grundfos UPSO 15-55..................................................................................................... 26
13.3 Heating circuit pump Grundfos UPM3 Auto L 50-70 130....................................................................... 27
13.3.1 Pump curve proportional pressure mode 2, PP2.............................................................................. 28
13.3.2 Change pump operating mode.......................................................................................................... 28
13.3.3 Key lock function............................................................................................................................... 28
13.4 Heating circuit pump Grundfos UPML 25-95 180, settings and capacity............................................... 29
13.4.1 Changing pump curve setting ........................................................................................................... 30
14 Fault finding pump..............................................................................................................31
14.1 Fault finding UMP3 pump....................................................................................................................... 31
15 Service instructions............................................................................................................32
15.1 Tap water service instructions................................................................................................................ 32
15.1.1 Tap water temperature too low ......................................................................................................... 32
15.1.2 Tap water temperature too high........................................................................................................ 32
15.1.3 Hot water temperature unstable........................................................................................................ 32
15.1.4 Noise in the DHWC system............................................................................................................... 33
15.2 Heating system service instructions....................................................................................................... 33
15.2.1 Heating system temperature too high or too low .............................................................................. 33
15.2.2 No heating......................................................................................................................................... 34
15.2.3 Heating system often needs topping up............................................................................................ 35
15.2.4 Heating temperature unstable........................................................................................................... 35
15.2.5 Noise in the radiator system.............................................................................................................. 36
16 Service actions for the installer.........................................................................................37
16.1 Check the function of the valve for hot water......................................................................................... 37
16.2 Check the heating actuator and valve function ...................................................................................... 38
16.3 Check the circulation pump Grundfos UPS............................................................................................ 38
16.4 Run the pump manually ......................................................................................................................... 39
16.5 Check the volume take-up and pressure equalizing of the expansion vessel ....................................... 39
17 Maintenance and repairs....................................................................................................40
17.1 Cleaning the district heating filter........................................................................................................... 40
17.2 Cleaning the heating circuit filter............................................................................................................ 40
17.3 Change the complete DHWC pump or pump components.................................................................... 41
17.4 Change the complete heating pump or pump components ................................................................... 42
17.5 Change the heating supply temperature sensor.................................................................................... 42
17.6 Change the outdoor temperature sensor ............................................................................................... 43
17.7 Change the heating actuator.................................................................................................................. 43
17.8 Change the heating valve....................................................................................................................... 44
17.9 Change the hot water valve.................................................................................................................... 44
17.10 Change the hotwater actuator and sensor............................................................................................. 45
17.11 Change the DHWC check valve............................................................................................................. 46
17.12 Change the expansion vessel................................................................................................................ 46
18 Options................................................................................................................................47
18.1 Safety thermostat ................................................................................................................................... 47
18.1.1 Parameters and recommended settings for under floor heating....................................................... 47
19 Operating data and performance.......................................................................................48
19.1 Operating data Mini Plus CB30-60H...................................................................................................... 48
19.2 Operating data Mini Plus CB18-54H...................................................................................................... 48

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1 General information
Cetetherm Mini Plus is a complete, ready-to-install heating network substation for heating and hot water. It is
designed for buildings with a primary connection to a heating network. Cetetherm has years of experience in
heating network technology and has developed Mini Plus with well-planned pipe work and with all components
easily accessible for inspection and possible future servicing.
1.1 Comfort
Mini Plus has fully-automatic temperature control for heating and hot water. The heating is controlled in relation
to outdoor temperature and/or desired room temperature. The hot water is controlled and maintained at the
desired temperature.
1.2 Installation
Well planned pipe work and readymade electrical wiring make installation very simple. A pre-programmed
controller and plug-and-socket connection provide further simplification, so that the substation can be started
without delay. The Mini Plus is designed for hanging on the wall.
Mini Plus is supplied fully wired. The wiring conforms to the applicable rules for CE marking and has undergone
electrical safety testing and function testing. For permanent installation, the substations must be connected via
an all-pole isolator switch.
The substation must be connected to a grounded wall socket.
1.3 Long-term security
All the plates and pipes in the heat exchanger are made of acid-resistant stainless steel for long life. All
components are adjusted together and undergo thorough function testing in accordance with Alfa Laval’s
ISO 9001:2008 quality assurance system. For future servicing requirements, all components are easily
accessible and individually replaceable.
1.4 CE-marking
Mini Plus is CE-marked to certify that the substation conforms to international safety regulations. To maintain
the validity of the CE marking, only identical replacement parts must be used.
1.5 Information about the document
All pictures in this document are general images.
Mini Plus is available in different models and levels of equipment.

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Installation, service and operating instruction
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1.6 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 district heating water are very high. Only qualified
technicians can work with the district heating 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.
Before the substation is connected to the electrical supply, make sure that the secondary 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.
When starting up the district heating 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 district heating circulation by first opening the valve in the district heating supply and then
return lines, to avoid pollutions in the system. Open the valves slowly to avoid pressure surges.
Do the same way with the heating circuit, first open the valve for heating return then supply.
Do not shut of the electrical supply to the operator control panel. 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
2.1 Operation
The temperature and pressure of the incoming heating network water from the culvert network are very high.
For this reason, only the heat from this water is used. The heating network water does not enter the heating
and hot water systems of the building.
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.
Mini Plus has automatic temperature control for heating and hot water. The heating circuit is controlled in
relation to outdoor temperature and/or desired room temperature by means of a controller 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.
The hot water temperature is controlled by a temperature control system which is set to about 55 ºC.
After adjustment, the Mini Plus 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.
2.2 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 variation causes unnecessary wear of
valves, actuators 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 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.
The heating system is topped up via the heating filler valves, see 15.2 Heating system service instructions. Be
sure to close the valves when the correct pressure is reached. The water used to top up the system contains
oxygen and may cause corrosion in the system. For this reason, the system should be topped up as seldom as
possible, at most once a year, when the heating system has been thoroughly bled and balanced.
Hot water temperature in apartments or one family houses can be set to about 55°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.
For setting and (if necessary) fine adjustment of the heating and hot water temperatures, see chapter 8.

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Installation, service and operating instruction
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3 Product overview
Picture 1
1
Heat exchanger for heating
18
Balancing valve DHWC
2
Heat exchanger for domestic hot water
19
Circulation pump DHWC
3
Connection box for electric power and
sensors
20
Check valve for DHWC
4
Control valve, heating circuit
21
Safety valve for heating circuit
5
Actuator, heating circuit
22
Filter for heating circuit
6
Supply temperature sensor, heating circuit
23
Pressure gauge for heating circuit
7
Outdoor temperature sensor (not in picture)
24
Circulation pump heating
8
Operator control panel with room thermostat
25
Safety thermostat (option)
9
Control valve for domestic hot water
26
Shutoff valves
10
Actuator and sensor for domestic hot water
A.
District Heating Supply
11
Temperature sensor connection, DH supply
B.
District Heating Return
12
Filter for district heating supply
C.
CW
13
Adapter for energy meter
D.
DHW
14
Temperature sensor connection, DH return
E.
Heat, Return
15
Check valve for cold water
F.
Heat, Supply
16
Safety valve for domestic hot water
G.
DHWC
17
Valve to top up the heating circuit

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Installation, service and operating instruction
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4 Installation
4.1 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 exchangers as this may weaken
them. Avoid lifting the unit by holding the heat exchangers.
Note: Risk of injury lifting heavy objects.
4.2 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 into 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 district heating supplier. The available differential pressure
should be at least 100 kPa and at most 600 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.
4.3 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, 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 5 Measure sketch Mini Plus.
•Install enclosed check valve for cold water in cold water pipe.
Picture 2; Installation of check valve in cold water pipe.
•Connect the pipe work to the connection points. Use the enclosed shutoff valves with flat contact face.
•Drainage pipes from safety valves 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. 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.
•Mount the outdoor temperature sensor on the north side of the building, 2 metres above the ground, or
higher. For installation of the outdoor temperature sensor, see 7.2 Installing the outdoor temperature
sensor.
•For installation of the operator control panel see 7.1 Using the control panel as a room thermostat.

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Installation, service and operating instruction
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4.4 Mounting options
•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 chapter 18.1 Safety thermostat.
4.5 Adjustments and settings
•Open incoming cold-water supply and fill the service water and heating circuits, bleeding off any
trapped air.
•Allow 5 minutes for the controller start up sequence and to regain functionality after a power cut.
See 7.3 Starting up and component control of control panel.
•Check the operation and opening pressures of the safety valves.
•Now 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. The temperature should be
approximately 55°C. It takes about 20 seconds to get stable tap water temperature.
See 15.1 Tap water service instructions for adjusting hot water temperature.
NOTE: Make sure that no cold water is mixed with the hot water while making this adjustment.
•Start the heating circulation pump with the highest output setting. Let the heating system heat up and
bleed the system again, see 15.2 Heating system service instructions. After final bleeding, the pressure
should not be less than 1.0 bar in winter and not less than 0.6 bar in summer.
•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.
•Activate the outdoor sensor (needed for heating curve control) and/or room temperature sensor via the
room panel. Se 7.4 Configure the control panel after installation.
•Set the day and time on the operator control panel. See 7.5 Setting the day and 7.6 Setting the time.
•Set the operating mode on control panel. See 8.1 Choosing the operating mode.
•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 district heating water.
4.6 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.
4.7 Commissioning advice
The controller has been set at the factory. If any function needs tuning, values can be changed regarding this
manual for parameter setting. Initially, the commissioning process should be carried out with the factory
settings. To activate Eco function or summer heating, see 9.3 Category 2 parameters: ECO-functions.

Cetetherm Mini Plus CM737
Installation, service and operating instruction
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5 Measure sketch Mini Plus
Picture 3

Cetetherm Mini Plus CM737
Installation, service and operating instruction
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6 Control panel with room thermostat CM737
6.1 General
The rom thermostat CM737 controls the supply temperature to the heating system. When connecting unit to the
power supply, the room thermostat verifies the connected sensors and then automatically chooses to control by
room or outdoor temperature sensor or both.
Features:
•Ergonomic user interface.
•Large LCD (Liquid Crystal Display) Screen.
•Four independent temperature levels per day, from 5°C to 35°C.
•Built-in Memory holds the user program indefinitely.
•Holiday button saves energy by letting you reduce the temperature for 1 to 99 days.
•7- days heating program to match your lifestyle, and maximizing energy savings.
Picture 4
1
LCD display
6
Temperature change buttons
11
Program buttons
2
Time display
7
Temperature enquiry button
12
Copy day button
3
Heating indicator
8
Operating mode buttons
13
Day select button
4
Day indicator
9
OK button, green
14
Time change buttons
5
Temperature display
10
Holiday function button
OK-button (9)
When changing settings/values in room thermostat, the numbers in the display is flashing.
Confirm the new settings with the green OK-button (9) and the new setting will be confirmed.

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Installation, service and operating instruction
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7 Installing and start up the control panel
7.1 Using the control panel as a room thermostat
The control panel can be used as a room thermostat.
Before installation make sure that the electrical power supply is disconnected.
Picture 5
Install the room thermostat in the living space according to following:
•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 7.4 Configure the control panel after
installation.

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Installation, service and operating instruction
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Picture 6

Cetetherm Mini Plus CM737
Installation, service and operating instruction
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7.2 Installing the outdoor temperature sensor
Connect the outdoor temperature sensor to the terminal strip in accordance with the electrical diagram, remove
any resistor.
With a conductor area of 0.6 mm2the maximum cable length is 50 metres and maximum 5Ω/conductor. When
the outdoor temperature sensor cable is connected to a terminal strip, the connecting cable must be long
enough for the controller and its mounting plate to be lifted off.
If the outdoor temperature sensor is connected later, for example in a construction period, the current must be
disconnected for a few minutes.
Set parameter 14 according to requested compensation; see 7.4 Configure the control panel after installation.
The installation must be connected to a grounded wall socket.
7.3 Starting up and component control of control panel
Note: The substation must be filled with water before starting the room thermostat, if not the pump can be
damage.
1. Put the electrical cable from the control panel into a wall outlet.
2. Check the heating actuator (knob turns) on and pump function. In start-up mode, the components
manoeuvre by the following schedule:
•10s actuator clockwise, if not closed at start
•10s actuator counter clockwise
•10s actuator clockwise
•10s pump runs
•150s actuator closes
After approximately another 4 minutes the room thermostat changes from start up to normal regulation.
3. Press the MAN (8) button for a fixed set point (no reduction) of the room temperature.
4. Adjust the room temperature with the increase/decrease buttons on the right (6).
By outdoor compensation this change represents a standard parallel shift of the heat curve, recalculated for
room temperature. For more details see chapter 8.5 Parallel adjustment of heating curve.
7.4 Configure the control panel after installation
The room thermostat can be configured in three different ways. All installation parameters can be found in the
parameter list, see 9Activation of installer parameters.
The control panel is pre-set to Outdoor compensation.
•Outdoor compensation, require a connected outdoor temperature sensor,
see 7.2 Installing the outdoor temperature sensor.
Set parameter 14:rC to 1.
•Room compensation, require a mounted room thermostat,
see 7.1 Using the control panel as a room thermostat.
Set parameter 14:rC to 0.
•Outdoor and room compensation, require a connected outdoor temperature sensor and a mounted
room thermostat see 7.2 Installing the outdoor temperature sensor and 7.1 Using the control panel as a
room thermostat.
Set parameter 14:rC to 2.

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Installation, service and operating instruction
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7.5 Setting the day
1. Press the DAY button to begin setting the day, (1-7=mon-sun).
Each press will move the day indicator one step forward.
After 7 it will start over again at 1.
Press the green button to confirm.
7.6 Setting the time
1. Press either of the or buttons once to enter timer setting mode.
The LCD screen flashes the time digits. When the unit is powered for the
first time the display shows 12:00.
2. Use the or buttons to set the correct time then press the green
button to confirm.
Each press of the buttons will change the time by one minute and holding them down will change the
time slowly at first and get progressively quicker.
NOTE: to leave this mode, press the AUTO, MAN or OFF buttons.

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Installation, service and operating instruction
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8 Operating the room thermostat CM737
8.1 Choosing the operating mode
The room thermostat can operate in three different modes; Automatic, Manual or Off.
To set the operating mode press either of the AUTO, MAN or OFF buttons. The screen indicates which mode is
currently active.
NOTE: Cetetherm recommends the mode MAN.
•MAN (manual) the room thermostat acts with a fixed set point throughout the day.
The set point can be adjusted from 5°C to 35°C by using the or buttons.
The thermostat will continue to maintain this temperature until another operating mode or temperature
is selected.
•AUTO (automatic) the room thermostat follows the built-in temperature program, default or modified.
A manually adjustment of the temperature with arrow “up” or “down” is only valid until next programmed
temperature change.
NOTE: The built-in heating program has been designed to provide normal comfort requirements, but to
customise the settings please see 8.6 Operating mode Auto.
•OFF the room thermostat controls to a minimum temperature. Default setting of 5°C acts as a frost
protection for your home.
8.2 Temperature Enquiry with the Info-button (7)
Each value will be displayed for 3 second before returning to show the initial screen.
NOTE! The initial screen shows different temperatures depending on if the outdoor temperature sensor is
connected and the setting of parameter 14:rC in the room thermostat.
•Target room temperature - with outdoor compensation.
•Current room temperature –with room compensation.
Press ones on the info-button , the display will show one of following three:
1. EXT above the clock and a temperature.
The outdoor temperature sensor is installed correct and the controls
the heating.
Displayed temperature is present outside temperature, according to
the sensor.
Press ones more on the Info-button, in 3 seconds, to show the
supply temperature. Check that the temperature is reasonable buy
carefully touching the supply pipe.
2. Flashing temperature and no EXT above the clock.
The temperature flashing is the set point according to room
compensation and the room thermostat controls the heating without
the outdoor temperature sensor.
Press ones more on the Info-button, within 3 seconds, to see the
value of the outdoor sensor.
3. EXT above the clock and ---- instead of the outdoor
temperature.
This means that the outdoor sensor or its cable is damaged or not
connected.
Press ones more on the Info-button, in 3 seconds, to show the
supply temperature. Check that the temperature is reasonable buy
carefully touching the supply pipe.

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8.3 Holiday function
The holiday function allows you to set a constant temperature (default = 10°C) for a specified number of days
(from 1 - 99 days). This saves energy and related costs when the house is empty, but resumes normal
operation on the day of return.
To set the Holiday function:
1. Ensure the room thermostat is running in AUTO or MAN operating modes.
2. Press the holiday button to display the holiday day’s counter and temperature setting, along with
the holiday indicator .
3. Press the or time buttons to set the holiday time (1-99 days) and press the green
button to confirm.
4. Press the or buttons to set the holiday temperature (5°C - 35°C) and press the green
button to confirm.
The room thermostat will now control to the new temperature for the set number of days that the home is
vacant. At midnight, the holiday counter will be reduced by one until the selected number of days have passed.
The room thermostat will then return to former operation as set by the MAN or AUTO mode.
To cancel the HOLIDAY function or to exit the function at any time: press the button a second time.
8.4 OTC heating curve
The CM737 controls the indoor temperature as a
function of the measured outside air temperature.
The heating curve is the ratio between the measured
outside air temperature and the calculated supply
water temperature.
The ideal heating curve is dependent on the type of
installation (radiators, convectors, etc.), the thermal
properties and the location of the property. A heating
curve ratio of 1 to 40 can be set. The figure shows
several heating curve ratios for a room temperature
setting of the 20°C without room temperature
compensation.
Supply water temperature (°C)
Heat curve 10 (15:OC) has been set at the factory.
.
Outside Temperature (°C)
Heating curve ratio is at room temperature setting of 20°C
Picture 7.
8.5 Parallel adjustment of heating curve
If any other room temperature set point than 20oC
is used the selected curve will be parallel
compensated.
Every change of the room temperature set point
from 20oC will change the supply temperature with
approximately 3oC. If the room temperature set
point is increased from 20oC to 21oC the supply
temperature will increase with approximately 3oC.
This example shows parallels of curve 10 by 19oC
and 21oC.
Supply water temperature (°C)
Outside Temperature (°C)
Picture 8

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Installation, service and operating instruction
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8.6 Operating mode Auto
8.6.1 The Built-in Heating Program
The built-in heating program has four temperature level changes per day that can be set between 3.00am and
2.50am the following day - allowing the evening temperature to maintain after midnight. Each temperature level
can be set between 5°C and 35°C, and adjusted in 0.5°C increments.
The factory default program for heating is as:
Monday to Friday (Day 1 to 5)
Period
1
2
3
4
Time
6:30
8:00
18:00
22:30
Temperature
21 °C
18 °C
21 °C
16 °C
Saturday & Sunday (Day 6 & 7)
Period
1
2
3
4
Time
6:30
8:00
18:00
22:30
Temperature
21 °C
18 °C
21 °C
16 °C
8.6.2 Reviewing the Heating Program
To review or edit the heating program use the PROGRAM or buttons to navigate between the four
individual programming periods.
Use the DAY button to step through each day of the week, so the complete 7-day heating program can be
reviewed or edited.
8.6.3 Temperature Override
During AUTO mode, the programmed temperature can be adjusted manually. The ‘target’ temperature will be
displayed and flash for 5 seconds - during this time the or or buttons can be used to modify the set
value.
NOTE:This temperature override is cancelled at the next programmed temperature change.
8.6.4 Disabling/enabling time periods
Any of the heating period from 2 to 4 can be removed from (or returned to) the heating program profile.
To disable or enable time periods:
1. To disable unwanted periods, go to the desired period (2 to 4) using the PROGRAM or buttons
to navigate, ensure the correct period is highlighted with the flashing square symbol.
Press and hold the button for at least 2 seconds and the display will indicate the period has been
removed from the program.
2. To enable periods again, follow the same procedure as above, navigating to the already disabled
period. To enable this period again, press and hold the button for at least 2 seconds.

Cetetherm Mini Plus CM737
Installation, service and operating instruction
18
8.6.5 Modifying the heating program
To change the heating program:
a) Press either of the PROGRAM or buttons to enter the
programming mode.
The time /temperature settings for period on Monday day 1 will
be flashing. The active period is highlighted by a flashing square
around the numbers at the bottom of the screen and the selected
day is shown with the day indicator.
b) To adjust the period, start time use the or buttons, the ‘OK?’ indicator will be displayed to
confirm the change. Holding the button down will change the time quickly.
Note: If you are pressing the or buttons and the display flashes the next period, it means the
next period will be pushed forward.
c) Once the required time is reached press the green button to confirm.
Note: If the original time setting did not require adjustment press the green button to move to
step ‘d’.
d) The temperature setting for period on Monday (Day 1) will now be flashing. To adjust this, press the
or buttons and confirm the setting again by pressing the green button.
e) The next time and temperature period will now be active. Adjust this by repeating steps b - d above
until all four periods are set or press the AUTO button to run the program as set, at any time.
Chose how to set the program for the next day:
f) Press the COPY DAY button to copy Monday’s program into Tuesday. The display will go blank apart
from the ‘non-flashing’ day indicator, which indicates the day copied and the ‘flashing’ target day to
copy the program to. To accept this day, press the green button. To select a different target day
press the DAY button until the ‘flashing’ day indicator is under the required day, and then accept it by
pressing the green button.
Note: Once the target day is confirmed it becomes the day that is copied if the COPY DAY button is
pressed again.
Or
Press the DAY button to move the day indicator to Tuesday (Day 2). The program for that day can then
be adjusted by following steps b to e. Programs for the remaining days can be set in the same way,
using the DAY button to move to the next day.
To exit the programming mode, select the desired operating mode by pressing the AUTO, MAN or OFF
buttons.
Note: To run the adjusted program; select the AUTO mode.