Compressors typically fail because of a system problem or other component. It is imperative that the problem be diagnosed and corrective measures put in place, or the replacement compressor will also fail. Field examination of a failed semi-hermetic compressor will usually reveal the cause of failure and will point to the system problem.
Worn pistons and cylinders with no evidence of overheating (air cooled compressors). Center and rear bearings worn or seized, dragging rotor/shorted stator, progressively scored crankshaft, worn or broken rods (suction cooled compressor).
Refrigeration Flood Back
Correct low load conditions; check for proper superheat at the compressor; install an accumulator to protect the compressor against uncontrollable liquid return.
Worn or scored rods/bearings. Broken rods from seizure. Crankshaft worn erratically.
Crankcase heater operation; install pump down solenoid.
Broken rods, reed valves or crankshaft, loose or broken valve backer bolts, blown head gasket.
Liquid and/or Oil Slugging
Check of proper superheat at the compressor; correct low load condition; install an accumulator; install a pump down solenoid. Check for crankcase oil overcharge.
Discolored valve plate, burned valve reeds, worn pistons, rings and cylinders, stator spot burn from metal debris.
High Discharge Temperature
Correct low load conditions; correct high discharge pressure conditions; insulate suction lines; provide correct compressor cooling.
All rods and bearings worn or scored, crankshaft uniformly scored, rods broken from seizure, little or no oil in crankcase.