TROUBLESHOOTING GUIDE
SYMPTOM
Low discharge pressure
Excessive noise (knocking)
Large quantity of oil in the
discharge air
NOTE: In an oil lubricated
compressor there will always
be a small amount of oil in the
air stream.
Water in discharge air/tank
POSSIBLE CAUSE(S)
1. Air demand exceeds pump capacity
2. Air leaks (fittings, tubing on
compressor, or plumbing outside of
system).
3. Restricted air intake
4. Blown gaskets
5. Leaking or damaged valves
1. Loose motor pulley or flywheel.
2. Loose fasteners on pump or motor.
3. Lack of oil in crankcase
4. Worn connecting rod
5. Worn piston pin bores
6. Piston hitting the valve plate
7. Noisy check valve in compressor
system
1. Worn piston rings
2. Compressor air intake restricted
3. Excessive oil in compressor
4. Wrong oil viscosity
Normal operation. The amount of water
increases with humid weather
CORRECTIVE ACTION
1. Reduce air demand or use a compressor with more
capacity.
2. Listen for escaping air. Apply soap solution to
all fittings and connections. Bubbles will appear
at points of leakage. Tighten or replace leaking
fittings or connections. Use pipe thread sealant.
3. Clean or replace the air filter element.
4. Replace any gaskets proven faulty on inspection.
5. Remove head and inspect for valve breakage,
misaligned valves, damaged valve seats, etc.
Replace defective parts and reassemble.
1. Tighten pulley / flywheel clamp bolts and set-
screws.
2. Tighten fasteners.
3. Check for proper oil level; if low, check for possible
damage to bearings. Dirty oil can cause excessive
wear.
4. Replace connecting rod. Maintain oil level and
change oil more frequently.
5. Remove piston assemblies from the compressor and
inspect for excess wear. Replace excessively worn
piston pin or pistons, as required. Maintain oil level
and change oil more frequently.
6. Remove the compressor head and valve plate
and inspect for carbon deposits or other foreign
matter on top of piston. Replace head and valve
plate using new gasket. See Lubrication section for
recommended oil.
7. Replace check valve.
1. Replace with new rings. Maintain oil level and
change oil more frequently.
2. Clean or replace filter. Check for other restrictions
in the intake system.
3. Drain down to full level.
4. Use Mobil 1
10W-30 or full synthetic.
®
1. Drain tank more often. At least daily.
2. Add a filter to reduce the amount of water in the
air line.
14
Install a new head gasket
each time the head is removed.
Do not disassemble check valve
with air pressure in tank.