The problem: A piston-type reciprocating compressor has valve damage, or the valves are not sealing for some reason. The result: an inefficient compressor. This is one of the most difficult service problems to diagnose because the system may still have some cooling capacity.
A common cause of premature reciprocating compressor failure is overheating. A recip that is running too hot will surely fail before its time. A service tech should always look for this potential problem while servicing any refrigeration system.