Symptom 2: The unit is turned on but the compressor is not starting
Symptom 1: The unit is turned on but the unit is not heating or cooling as expected
14.2 General symptoms
POSSIBLE CAUSES
CORRECTIVE ACTION
The unit maybe operate
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)
Symptom 4: The water pressure relief valve opens
POSSIBLE CAUSES
CORRECTIVE ACTION
There is air in the system.
Purge air.
Water pressure at pump
inlet is too small.
POSSIBLE CAUSES
CORRECTIVE ACTION
The expansion vessel is broken.
Replace the expansion vessel.
The filling water pressure
in the installation is
higher than 0.3MPa.
Make sure that the filling water pressure in the installation is about
0.10~0.20MPa.
Symptom 5: The water pressure relief valve leaks
POSSIBLE CAUSES
CORRECTIVE ACTION
Dirt is blocking the water
pressure relief valve
outlet.
•
Check for correct operation of the pressure relief valve by turning the
black 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.
POSSIBLE CAUSES
CORRECTIVE ACTION
The temperature setting is not correct.
The water flow is too small.
The water volume in the installation is
too small.
Make sure that the water volume in the installation is above the minimum
required value. Please refer to 9.3.2 Water volume and sizing expansion
vessels.
Check the parameters (T4HMAX, T4HMIN in heating mode; T4CMAX, T4CMIN
in cooling mode). For the parameter setting range, please refer to 11.1 Setting
parameters.
47
• Check that all shut off valves of the water circuit are in the right position.
• Check if the water filter is plugged.
• Make sure there is no air in the water system.
• Check the water pressure.
The water pressure must be≥1.5 bar.
• Make sure that the expansion vessel is not broken.
• Check the water pressure.
The water pressure must be ≥1.5 bar.
• Check that the expansion vessel is not broken.
• Check that the setting of the pre- pressure of the expansion
vessel is correct.
