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Heat Pump Troubleshooting
1. Symptom: Compressor will not start
Possible Causes
High pressure switch open
Compressor overload opened
No power to module
Phase monitor open or tripped
Breaker tripped
Overcurrent
Ambient temperature is lower than 0° F
2. Symptom: Compressor will not run
Possible Causes
Ambient temperature is lower than -5° F
Main switch open or circuit breakers open
Fuse is blown
Investigate for possible overloading
Defective contactor or coil
3. Symptom: Compressor has excessive noise or vibration
Possible Causes
Flooding of refrigerant back to compressor
Improper phase sequence
Improper or worn compressor supports (vibration-isolating mounting)
Faulty crankcase heater
4. Symptom: Compressor Loading/Unloading Cycles Too Short
Possible Causes
Temperature differential set too low
Incorrect liquid temperature settings
Insufficient evaporator water flow
Low system liquid/water volume
5. Symptom: Compressor loses oil
Possible Causes
Low refrigerant charge
Oil trapped in the system
Defective crankcase heater
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Potential Solutions
High pressure event has occurred; Check fan settings and functionality;
Check obstructed coils; Check pressure switch functionality
Allow motor to cool and reset; High amp load/floodback; Compressor
operating outside of operating envelope
Check breakers and fuses; Energize from module electrical and control panel
Check phase sequence, unbalanced voltage, Overvoltage, Undervoltage;
Loss of phase
Reset breaker; Check amp draw, high refrigeration pressure, low voltage, and
lose connection
Check overload (circuit breaker, compressor grounded,..)
Ambient temperature should be above 0° F
Potential Solutions
Ambient temperature should be above -5° F
Check circuits and motor winding for shorts or grounds
Replace fuse or reset breakers
Overloads are auto-reset. Monitor to assure the overload does not re-occur
Determine type and cause. Correct fault before resetting safety
Potential Solutions
Check setting of expansion valve; Check crankcase heater
Check phase sequence
Replace supports
Replace crankcase heater
Potential Solutions
Ramp/set temperature differential setpoint; Check stage up/down settings
Select proper control settings
Check flow rate
Water system volume needs to be increased
Potential Solutions
Check for leaks and repair. Add refrigerant to proper charge
Low refrigerant velocity caused by operation outside operating envelope;
Check fan settings and functionality in heating mode
Replace crankcase heater
ARTC-SVX006A-EN
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