Instruction manual

QR-25 Series Quincy Compressor

52201-107, December 2012 32 3501 Wismann Lane, Quincy IL - 62305-3116

Trouble Probable Cause

Intercooler pressure •Compressor valves or valve unloaders in ﬁrst stage not functioning

abnormally low properly or defective

(Two stage models only) •Restricted air inlet ﬁlter or suction line

•Pilot valve or pressure switch set incor rectly or defective

•Pressurized air at valve unloader not vent ing properly when demand for

air is re quired; vent passage at hydraulic unloader or three-way valve

could be plugged

•Compressor valve or head gasket leaking

•Worn piston rings

•Defective pressure gauge

•Leaking air at intercooler or intercooler connections

Compressor overheats •Clogged intake system

•Defective compressor valves

•Pressure setting too high

•Clogged intercooler, internally or exter nally

•Inadequate ventilation, or recirculation of hot air

•Pulley/sheave rotation wrong

•Incorrect speed

•Running clearances insufﬁcient (piston to cylinder wall or running gear)

•Lubrication inadequate

•Compressor incorrectly sized

High discharge •Compressor valve assemblies defective

temperature •Discharge pressure too high

•Inadequate ventilation or hot air recirculat ing

•Cooling surfaces of compressor or inter cooler excessively dirty

•Internal surface of heat exchanger fouled

•Ambient temperature too high

•Scored or excessively worn cylinder walls

Compressor knocks •Head clearance insufﬁcient

•Piston loose in cylinder bore, cylinder bore worn, piston or piston rings

worn

•Worn rods or main bearing

•Wrong pressure setting, discharge pressure excessive

•Crankcase lubrication inadequate

•Loose pulley/sheave

•Compressor valve assemblies loose