Problem – Loud Compressor Noise; Problem – Shrieking, Whistling Noise; Problem – Noise – Miscellaneous - Danfoss DHP-AQ Mini Service Instructions Manual

Table 16. Problem – Loud compressor noise
Cause
1. Phase drop.
The compressor attempts to start or
operates on two phases (only applies
to 3 phase heat pumps) .
2. Touching pipes – vibrations.
3. Compressor fault
Table 17. Problem – Shrieking, whistling noise
Cause
1. Noise from the soft-starter.
2. The compressor's safety valve
opens.
Table 18. Problem – Noise – miscellaneous
Cause
1. Vibrating protective sleeves on the
pressure switches.
2. Vibration noise from the electrical
installation.
22 – Service instructions VMGFJ102
Troubleshooting
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 voltage for all
electrical components all the way
to the compressor, see wiring dia-
gram.
Establish which pipe(s) is/are causing the
problem.
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.
Troubleshooting
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.
The compressor has an integrated safety
valve that opens when the pressure differ-
ence between high and low pressure sides
is too large. A whistling sound can be
heard during pressure equalisation. Use a
manometer to check at which pressure
differential pressure equalisation occurs.
Troubleshooting
Establish where the vibration noise is com-
ing from.
Check for electrical steps or similar devices
screwed to the heat pump and wall. These
can cause vibrations and noise.
Remedy
Check where the phase drop is and rec-
tify.
Try to remove the contact:
If the compressor is defective, replace it.
Remedy
If the soft-starter is defective, replace it.
Replace the compressor if the valve
opens at too low pressure or when the
compressor is stationary.
Remedy
Prevent the protection sleeve vibrating
by using insulation tape for example.
Carry out according to the installation
instructions.