Liquid slugging is the phenomenon of liquid entering the cylinder of a reciprocating compressor, a common cause of failure. Under normal conditions, the intake and output of a compressor cylinder is entirely vapor or gas, when a liquid accumulates at the suction port liquid slugging can occur.

What causes liquid slugging?

If liquid refrigerant is entering the compressor, liquid will fall directly into the crankcase oil and eventually be flashed. ... This causes oil foaming and excessively high crankcase pressures. Refrigerant and oil droplets will soon reach the compressor's cylinder and slugging will soon occur.

What can cause liquid slugging with liquid refrigerant?

Slugging can result in broken valves, broken head gaskets, broken connecting rods, and other major compressor damage. Refrigerant-cooled semihermetic compressors will often draw liquid from the suction line through hot motor windings in the motor barrel, which will assist in vaporizing any liquid.