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When a safety device was activated, stop the unit and find out why the safety device was activated before resetting it. Under no
circumstances can safety devices be bridged or changed to a value other than the factory setting. If the cause of the problem
cannot be found, call your local dealer.
If the pressure relief valve is not working correctly and is to be replaced, always reconnect the flexible hose attached to the
pressure relief valve to avoid water dripping out of the unit!
Before starting the troubleshooting procedure, carry out a thorough visual inspection of the unit and look for obvious defects
such as loose connections or defective wiring.
For problems related to the optional solar kit for domestic water heating, refer to the troubleshooting in the Installation
& Owner's manual for that kit.
NOTE
When carrying out an inspection on the switch box of the unit, always make sure that the main switch of the unit is
switched off.
WARNING
This section provides useful information for diagnosing and correcting certain troubles which may occur in the unit.
This troubleshooting and related corrective actions may only be carried out by your local technician.
13 TROUBLE SHOOTING
13.1 General guidelines
Symptom 2: The unit is turned on but the compressor is not starting (space heating or domestic water heating)
POSSIBLE CAUSES
CORRECTIVE ACTION
The unit must start up
out of its operation range
(the water temperature
is too low).
In case of low water temperature, the system utilizes the backup heater to
reach the minimum water temperature
first (12°C).
• Check that the backup heater power supply is correct.
• Check that the backup heater thermal fuse is closed.
• Check that the backup heater thermal protector is not activated.
• Check that the backup heater contactors are not broken.
Symptom 1: The unit is turned on but the unit is not heating or cooling as expected
13.2 General symptoms
POSSIBLE CAUSES
CORRECTIVE ACTION
The temperature setting
is not correct.
Check the controller set point.T4HMAX,T4HMIN in heat mode.
T4CMAX,T4CMIN in cool mode.T4DHWMAX,T4DHWMIN
in DHW mode.
The water flow is too low.
• Check that all shut off valves of the water circuit are
completely open.
• Check if the water filter needs cleaning.
• Make sure there is no air in the system (purge air).
• Check on the manometer that there is sufficient water pressure.
The water pressure must be>1 bar (water is cold).
• Make sure that the expansion vessel is not broken.
• Check that the resistance in the water circuit is not too high
for the pump.
The water volume in the
installation is too low.
Make sure that the water volume in the installation is above
the minimum required value (refer to "9.3 water piping/
Checking the water volume and expansion vessel pre-pressure").
