Page 245 - Intro Predictive Maintenance

236 An Introduction to Predictive Maintenance

Table 10–10b Common Failure Modes of Reciprocating Compressors

THE PROBLEM

Air Discharge Temperature Above Normal Carbonaceous Deposits Abnormal Compressor Fails to Start Compressor Fails to Unload Compressor Noisy or Knocks Compressor Parts Overheat Crankcase Oil Pressure Low Crankcase Water Accumulation Delivery Less Than Rated Capacity Discharge Pressure Below Normal Excessive Comp

THE CAUSES Motor Over-Heating Starts Too Often
Discharge Line Restricted
Discharge Pressure Above Rating
Electrical Conditions Wrong
Excessive Number of Starts
Excitation Inadequate
Foundation Bolts Loose
Foundation Too Small
Foundation Uneven–Unit Rocks
Fuses Blown
Gaskets Leak H L H L H H
Gauge Defective
Gear Pump Worn/Defective
Grout, Improperly Placed
Intake Filter Clogged
Intake Pipe Restricted, Too Small, Too Long
Intercooler, Drain More Often
Intercooler Leaks
Intercooler Passages Clogged
Intercooler Pressure Too High
Intercooler Vibrating
Leveling Wedges Left Under Compressor
Liquid Carry-Over

impact that occurs when each piston changes directions (i.e., two impacts occur during
one complete crankshaft rotation).

Valves
Valve failure is the dominant failure mode for reciprocating compressors. Because of
their high cyclic rate, which exceeds 80 million cycles per year, inlet and discharge
valves tend to work hard and crack.

Lubrication System
Poor maintenance of lubrication system components, such as filters and strainers,
typically causes premature failure. Such maintenance is crucial to reciprocating