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13.2 General symptoms
Symptom 1: The unit is turned on but the unit is not heating or cooling as expected
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 prepressure").
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 3: Pump is making noise (cavitation)
POSSIBLE CAUSES
CORRECTIVE ACTION
There is air in the system.
Purge air.
Water pressure at pump inlet is too low.
• Check on the manometer that there is sufficient water pressure.
The water pressure must be > 1 bar (water is cold).
• Check that the manometer is not broken.
• Check that the expansion vessel is not broken.
• Check that the setting of the pre-pressure of the expansion
vessel is correct (refer to "9.3 water piping/Checking the
water volume and expansion vessel pre-pressure").
