Product Manual

QT/QTS Series Quincy Compressor
50161-108, January 2013 42 3501 Wismann Lane, Quincy Ill. - 62305-3116
Trouble Probable Cause
Excessive drive belt wear •Pulley/sheave out of alignment
•Belt too loose or too tight
•Belt slipping
•Pulley/sheave wobbling
•Pulley/sheave groove damaged or rough
•Incorrect belts
Low oil pressure •Oil sump strainer plugged
•Excessive leakage at crankshaft seals
•Low oil level
•Oil pump incorrectly assembled to the bear ing carrier (“o”ring not
properly located between oil pump body & bearing carrier)
•Oil pressure adjusting screw not set properly
•Defective oil pressure gauge
Compressor loads •Air receiver too small
and unloads excessively •Compressor valves or unloaders defective
•Excessive system leakage
•Compressor operating at incorrect speed
•Unloader pilot differential set too close
•Pressure switch defective
Defective pressure switch •Moisture &/or oil buildup on the pressure switch diaphragm
•Ruptured diaphragm
•Burned contact points
•Plugged air passage from the receiver to the pressure switch
•Loose electrical connection
Excessive air pressure •Air pressure gauge inaccurate
in air receiver •Leaks in unloader piping system
•Defective compressor head unloader
•Pilot valve or pressure switch set incor rectly or defective
•Pressure switch wired incorrectly
•Tube to compressor head unloader plugged
Excessive •Intercooler restricted or plugged
intercooler pressure •Compressor valves in second stage broken or not functioning properly
•Pilot valve or pressure switch set incor rectly or defective