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evaporator, on fan
guard, or blades.
Defective defrost thermostat or timer.
Replace defective component
Too many defrosts
Reduce the number of defrosts
System troubleshooting.
symptoms
Possible causes
Solution
Compressor not
running
Main switch open
Close switch
Blown fuse
Check electrical circuits and motor
winding for shorts or grounds.
Replace fuse after fault is corrected.
Loose wiring
Check all wire junctions. Tighten all
terminal screws.
System cable shut down
Replace shutdown cable.
Thermal overload tripped
Overloads are automatically reset.
Check unit when unit come back on
line.
Defective contactor or contactor coil
Replace or repair
System shut down by safety devices.
Check cause of shut down
Liquid line solenoid not open
Repair or replace coil
Noisy
Compressor
Flooding of liquid refrigerant into crankcase Check expansion valve setting
Improper piping support on suction or liquid
line.
Relocate add hangers.
Worn compressor.
Replace compressor
High discharge
pressure.
Non-condensable in system.
Remove non-condensable.
Too much refrigerant
Remove excess refrigerant
Discharge shut off valve partially closed
Open valve
Fan not running
Check electrical circuit and fuse.
Dirty condenser coil
Clean condenser coil
Low discharge
pressure.
Faulty condenser temperature controls
Check head pressure control
Suction shut off valve partially closed
Open valve
Insufficient refrigerant
Check leaks. Add charge.
Low suction pressure
See corrective steps for low suction
pressure.
symptoms
Possible causes
Solution
High suction Excessive loads
Reduce load.
