Dantherm CDP 85 - Page 24

Fault nding guide: Fault nding
Display text
Type Fault Unit behaviour Possible cause Fault nding Solution(s)
LP Error Alarm LP
Error
LP Error reoccurring persis- tently Unit will pause and restart continously No or irregular noise com- ing from compressor Evaporator coil can build up a small amount of ice around expansion valve No or limited condensate being produced
HP switch trip Verify if HP switch has been tripped due to prior HP
error
Press HP switch reset button
Refrigeration circuit leak causing loss of refrigerant
- conrm compressor is running - conrm fan is running - conrm solenoid valve is closed (no hissing sound from valve)
Repair refrigeration circuit
Compressor malfunction Compressor does not start at all:
- Conrm contactor K1 is functional - Conrm there is voltage at compressor terminals.
Replace compressor
Compressor attempts to start but will not run (click- ing/humming from compressor): - Conrm that compressor voltage is within +/- 10% of nominal supply voltage - Conrm run capacitor / hard start capacitor (if installed) is within specications
Replace run capacitor / hard start capacitor (if installed) Replace compressor
Thermostatic Expansion Valve (TEV) defective
Verify if TEV is visually damaged: Check for cracks and/or corrosion in TEV head / cap- illary tube / TEV sensor bulb NOTE: The TEV can malfunction even without exter- nally visible damage
Replace TEV
Unit seemingly functions normally with no apparent fault. Evaporator coil cold, condenser coil warm. Permanent or periodic LP Error
Defective temperature sensor for evaporator coil or condensor outlet tube.
Verify temperature sensor resistance (ohm)* Replace sensor
Sensor wire break Verify sensor wire integrity Bad contact to evaporator coil / condensor outlet tube
Verify if sensor is xed to the tube Re-t sensor
Bad connection to Control- ler
Verify plug is connected to controller Clean plug / reconnect
to Controller
Controller failure Verify 12VDC controller supply voltage Replace controller
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