27
D1 Compressor safety
Compressor stops.
Cause
Measure
Compressor fault:
■
Thermal compressor relay or safety element of full
wave soft starter has responded.
■
Phase monitor has recognised a fault.
■
Phase monitor faulty.
■
Reset compressor thermal relay, check thermal relay
setting, restore delivered condition at control unit
(
"Standard setting"
).
■
Check compressor power connections. Check the
winding resistance of the compressor motor. Check
phase sequence on compressor.
The switching signal of the thermal relay/motor protec-
tion can be checked at terminal 215.7: See "Main PCB".
0 V
Thermal relay/motor overload relay has re-
sponded.
230 V~ Thermal relay/motor overload relay has not re-
sponded.
Note
The internal motor overload relay prevents re-enabling
of the compressor for 1 to 3 h if the motor overheats.
D3 Low pressure
Compressor stops.
Cause
Measure
Low pressure fault:
■
Heat pump is faulty.
■
Low pressure sensor has issued a fault message.
■
Low pressure sensor faulty.
■
Have heat pump checked by a refrigeration engineer.
■
Check pressure gauge and shut-off devices in the pri-
mary circuit.
■
Check low pressure sensor, lead and EEV PCB; re-
place if necessary.
D4 Control high pressure
Compressor stops.
Cause
Measure
High pressure fault:
■
Air in the secondary circuit
■
No flow rate in the secondary circuit
■
Condenser contaminated
■
High pressure sensor faulty
■
Vent the secondary circuit.
■
Check the system pressure.
■
Check secondary circuit flow rate.
■
Flush heating circuits.
Note
In rare cases a high pressure fault can occur, e.g. in the
event of high flow temperatures in the secondary circuit.
If this occurs several times in succession, check the
heat pump and parameter settings of the refrigerant cir-
cuit.
Troubleshooting
Message overview
(cont.)
5800 917 GB
Maintenance
