CAUTION
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.
When a safety device was activated, stop the unit and find out why
the safety device was activated before resetting it. Under no
circumstances safety devices may 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!
For problems related to the optional solar kit for domestic
water heating, refer to the troubleshooting in the Installation
& owner's manual of that kit.
9.2 General symptoms
Symptom 1: The unit is turned on but the unit is not heating or
cooling as expected
POSSIBLE CAUSES
The temperature setting
Check the controller set point. T4HMAX,
is not correct.
T4HMIN in heat mode.T4CMAX,T4CMIN
in cool mode. T4DHWMAX, T4DHWMIN
in DHW mode.
The water flow is too
• Check that all shut off valves of the
low.
• Check if the water filter needs cleaning.
• Make sure there is no air in the system
• Check on the manometer that there is
• Make sure that the expansion vessel
• Check that the resistance in the water
The water volume in the
Make sure that the water volume in the
installation is too low.
installation is above the minimum
required value (refer to "Water
pipework/Checking the water volume
and expansion vessel pre-pressure").
Symptom 2: The unit is turned on but the compressor is not
starting (space heating or domestic water heating)
POSSIBLE CAUSES
The unit must start up
In case of low water temperature, the
out of its operation range
system utilizes the backup heater to
(the water temperature
reach the minimum water temperature
is too low).
first (12°C).
• Check that the backup heater
• Check that the backup heater
• Check that the backup heater
• Check that the backup heater
NOTE
CORRECTIVE ACTION
water circuit are completely open.
(purge air).
sufficient water pressure. The water
pressure must be>1 bar (water is cold).
is not broken.
circuit is not too high for the pump
CORRECTIVE ACTION
power supply is correct.
thermal fuse is closed.
thermal protector is not activated.
contactors are not broken.
Symptom 3: Pump is making noise (cavitation)
POSSIBLE CAUSES
There is air in the system. Purge air.
Water pressure at pump
inlet is too low.
Symptom 4: The water pressure relief valve opens
POSSIBLE CAUSES
The expansion vessel is
broken.
The filling water pressure
in the installation is
higher than 0.3MPa.
Symptom 5: The water pressure relief valve leaks
POSSIBLE CAUSES
Dirt is blocking the water
pressure relief valve
outlet.
Symptom 6: Space heating capacity shortage at low outdoor
temperatures
POSSIBLE CAUSES
Backup heater operation
is not activated.
Too much heat pump
capacity is used for
heating domestic hot
water (applies only to
installations with a
domestic hot water tank).
43
CORRECTIVE ACTION
• 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 "Water
pipework/Checking the water volume
and expansion vessel pre-pressure").
CORRECTIVE ACTION
Replace the expansion vessel.
Make sure that the filling water pressure
in the installation is about
0.15~0.20MPa (refer to "Water
pipework/Checking the water volume
and expansion vessel pre-pressure").
CORRECTIVE ACTION
Check for correct operation of the
pressure relief valve by turning the
red knob on the valve counter
clockwise:
• If you do not hear a clacking sound,
contact your local dealer.
• In case the water keeps running out
of the unit, close both the water inlet
and outlet shut-off valves first and
then contact your local dealer.
CORRECTIVE ACTION
Check that the "OTHER HEATING
SOURCE/ BACKUP HEATER" is enabled,
see "Field settings"
Check whether or not the thermal protector
of the backup heater has been activated
(refer to "Switch box main components",
"Backup heater thermal protector"
for location of the reset button).
Check if booster heater is running, the
backup heater and booster heater can't
operate simultaneously.
Check that the 't_DHWHP_MAX' and
"t_DHWHP_RESTRICT" are
configured appropriately:
• Make sure that the 'DHW PRIORITY' in
the user interface is disabled.
• Raise the "T4_TBH_ON" in the user
interface/FOR SERVICEMAN to activate
the booster heater for domestic water
heating。
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