Danfoss DHP-AQ Series, Service Instructions Manual

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3 Troubleshooting
3.1 Alarm
In event of alarm this is indicated in the display with the text ALARM and an alarm message, see following table. For alarms that are not
reset automatically acknowledgement is required. Acknowledge the alarm by setting the heat pump to operating mode OFF and then
back to the desired operating mode.
Message Meaning
MOTOR P COMP.ERROR The compressor motor protection has deployed.
MOTOR P FAN ERROR The fan motor protection has deployed.
EL. HEATER ERROR The electrical heater overheating protection has deployed.
HEAT / PRESSURE ERROR The expected pressure and temperature change in the refrigerant circuit has not happened in the
correct way at compressor start.
LOW PRESSURE ERROR Evaporation pressure has fallen too low.
LOW PRESSURE TRANSDUCER Fault in low pressure transmitter alternatively cable fault.
HIGH PRESSURE ERROR High pressure switch has deployed.
LOW HEAT CIR. FLOW The flow sensor has registered too low a flow.
MAX TEMP ELEC. HW Too high temperature in heat pump junction box/electrical cabinet.
NO. OF TRIES X/5(where X=1…5) Circulation pump is jammed. Start attempt made.
HEATING CIRC. PUMP
Circulation pump is jammed.
HEATING SYSTEM PUMP Circulation pump is jammed.
OUTDOOR SENSOR Sensor fault alternatively cable fault.
DEFROST SENSOR Sensor fault alternatively cable fault. Defrost sensor.
SUPPLY LINE SENSOR Sensor fault alternatively cable fault. Supply line sensor.
SYSTEM SUPPLY LINE SENSOR Sensor fault alternatively cable fault. System supply line sensor.
RETURN LINE SENSOR Sensor fault alternatively cable fault. Return line sensor.
HIGH RETURN LINE TEMP Return line temperature too high
BUFFER TANK SENSOR Sensor fault alternatively cable fault.
HGW SENSOR Sensor fault alternatively cable fault.
HOT WATER SENSOR Sensor fault alternatively cable fault (the lower sensor, Start sensor).
HOT WATER TOP Sensor fault alternatively cable fault.
FAILSAFE MODE Sensor fault alternatively cable fault on one of the refrigerant sensors. The heat pump goes to fail-
safe mode and defrosts on time.
REFR.1 SENSOR Sensor fault alternatively cable fault. Refrigerant sensor 1
REFR.2 SENSOR Sensor fault alternatively cable fault. Refrigerant sensor 2
LOW RETURN TEMP 1 The return line temperature is too low to start a defrosting.
LOW RETURN TEMP 2 The return line has fallen too low during defrosting.
LOW EVAP. TEMP 1 Evaporation temperature too low.
LOW EVAP. TEMP 2 Too great a deviation in evaporation temperature average value.
SUCTION TEMP SENSOR Sensor fault alternatively cable fault.
ROOM SENSOR Sensor fault alternatively cable fault.
DISCHARGE PIPE SENSOR Sensor fault alternatively cable fault.
DISTR. CIR. 1 SENSOR Sensor fault alternatively cable fault.
DISTR. CIR. 2 SENSOR Sensor fault alternatively cable fault.
POOL SENSOR Sensor fault alternatively cable fault.
COM. ERROR HP-CARD Communication broken between display card and heat pump card (outdoor).
COM. ERROR HUB-CARD Communication broken between display card and hub card (indoor).
Service Instructions DHP-AQ
VMGFJ202 Danfoss Heating Solutions
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