Quincy Compressor QR-25 Series Instruction Manual page 34

Trouble
Intercooler pressure
abnormally low
(Two stage models only)
Compressor overheats
High discharge
temperature
Compressor knocks
QR-25 Series
52201-107, December 2012
Probable Cause
•Compressor valves or valve unloaders in first stage not functioning
properly or defective
•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
•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
•Compressor valve assemblies defective
•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
•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
34
Quincy Compressor
3501 Wismann Lane, Quincy IL - 62305-3116