TROUBLESHOOTING GUIDE
PROBLEM
POSSIBLE CAUSE
CORRECTIVE ACTION
Insufficient
output, low
discharge
pressure
Clogged inlet filter
Clean or replace as
necessary
Leaks in air lines, air
valves, fittings, etc…
Replace worn
components as
necessary
Drive belts slipping
Tension V-belts
Drain valve left open
Close drain valve
Defective pressure gauge
Replace pressure gauge
Compressor incorrectly
sized
Leaking head gasket
Replace head gasket
Dirty or plugged inter
cooler tubes
Remove and clean inter
cooler tubes
Unloader pilot or pressure
switch adjustment too low,
or defective
Make necessary
adjustments
Worn or defective
compressor valves
Replace worn parts
Worn piston, worn out
rings
Replace worn parts
Restrictive check valve
Clean check valve and
replace if necessary
Motor stalls
Faulty unloader/check
valve
Replace unloader or
check valve
Valves incorrectly installed
Install valves correctly
Drive belts too tight
Tension V-belts
Compressor
knocks
Compressor valves loose
or broken
Check and replace worn
or broken valves
Inspect check valve, it may
knock at low pressures
Remove and clean check
valve
Piston rings not
seated
Compressor not run long
enough to seat rings
Allow 100 hours of
normal operation for new
rings to seat
Wrong oil being used,
wrong viscosity
Drain and replace with
proper oil
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