Problem – Loud compressor noise
Cause
Troubleshooting
Remedy
1. Phase drop.
The compressor attempts to
start or operates on two
phases (only applies to 3
phase heat pumps) .
1. Check that there is 400 V between incoming phases
on the heat pump.
2. If there is supply to the heat pump, measure the volt-
age for all electrical components all the way to the
compressor, see wiring diagram.
Check where the phase drop is and rectify.
2. Touching pipes – vibra-
tions.
Establish which pipe(s) is/are causing the problem.
Try to remove the contact:
3. Compressor fault
Determine whether the compressor is unusually loud.
▪
Check with a voltmeter at a point before and after the
soft starter. The measurement values should not dif-
fer.
If the compressor is defective, replace it.
Problem – Shrieking, whistling noise
Cause
Troubleshooting
Remedy
1. Noise from the soft-start-
er.
Measurement check the input and output phases for the
soft-starter as well as the control signals from the heat
pump card, see wiring diagram.
If the soft-starter is defective, replace it.
2. The compressor’s safety
valve opens.
The compressor has an integrated safety valve that opens
when the pressure difference between high and low pres-
sure sides is too large. A whistling sound can be heard dur-
ing pressure equalisation. Use a manometer to check at
which pressure differential pressure equalisation occurs.
Replace the compressor if the valve opens
at too low pressure or when the compres-
sor is stationary.
Problem – Noise – miscellaneous
Cause
Troubleshooting
Remedy
1. Vibrating protective
sleeves on the pressure
switches.
Establish where the vibration noise is coming from.
Prevent the protection sleeve vibrating by
using insulation tape for example.
2. Vibration noise from the
electrical installation.
Check for electrical steps or similar devices screwed to the
heat pump and wall. These can cause vibrations and noise.
Carry out according to the installation in-
structions.
3.5.4
Hot-water
Problem – Temperature and/or quantity
Cause
Troubleshooting
Remedy
1. Defective 3-way valve mo-
tor.
Check the function of the reversing valve by test running it
manually.
If the motor is defective, replace it.
2. Jammed reversing valve.
The valve is not secure and
releases hot water to the ra-
diators during hot water
production.
Detach the motor and test closing and opening the valve
by turning the shaft by hand.
If it jams, replace with a new one.
3. Air in TWS coil or water
outer jacket.
During hot water production:
▪
Listen for air.
▪
Check the temperature difference between supply
and return line.
Bleed the system.
A Large temperature difference can indi-
cate air in the system.
4. Start temperature set too
high for hot water produc-
tion.
Check that the start temperature is correctly set. Should
not be set above the factory set value.
▪
If the start value is set too high, reduce
it to the factory set value.
Service Instructions
DHP-AQ
VMGFJ202
Danfoss Heating Solutions
22
