Danfoss DHP-A Service Instructions Manual page 44

Cause
6. Defective compressor (applies to 3-
phase heat pumps).
7. Alarm from the overload protection
on the brine pump (only certain heat
pump models).
8. Alarm from single phase soft starter. Check the fault cause using the soft start
Table 16. Problem – Alarm sensor (all)
Cause
Sensor fault alternatively cable fault.
Table 17. Problem – Incorrect phase sequence
Cause
The incoming phases have the incor-
rect sequence (only applies to 3-phase
heat pumps).
42 – Service instructions VMGFC302
Troubleshooting
Measurement check the voltage on the
three phases (each to zero) at the com-
pressor. There must not be any large devi-
ation between the phases. If measure-
ment checking the winding's resistance
the same value must be on all three wind-
ings.
Switch the heat pump off and on. If the
alarm remains check the WSK switch in
the brine pump.
LEDs.
Troubleshooting
•
When reading the resistance of the
sensors, the sensor leads must first
be disconnected from the control
equipment or terminal block.
•
First take a reading from the sensor
including cable and check against
the ohm table in Measurement
points.
•
If the read off value does not corre-
spond with the table, only measure
the sensor and check the ohm table
in Measurement points.
Troubleshooting
•
If the text ERR PHASE SEQ. appears in
the display when the heat pump is
powered, (only appears in the first 10
minutes) this means that the phases
have the incorrect sequence.
•
When the compressor is running,
check the pressure pipe temperature
by feeling the pressure pipe. If the
phases are correctly sequenced it
should be hot (not just warm) even a
distance from the compressor.
•
When the compressor runs with the
phases incorrectly sequenced a
strange noise may be heard (loud,
rattling) when the compressor runs
backwards.
Remedy
If the compressor is defective, replace it.
If the brine pump is defective, replace it.
Remedy
If the sensor gives a correct value, the
cable is defective.
If the sensor does not give a correct
value, the sensor is defective.
Remedy
If the phases are in the incorrect order,
switch two incoming phases at the main
terminal block and recheck according to
the troubleshooting window.