TROUBLESHOOTING GUIDE
SYMPTOM
POSSIBLE CAUSE(S)
CORRECTIVE ACTION
Compressor will not run
1. Unit is plugged into extension cord
1. Remove extension cord or use larger gauge
extension cord.
2. No electrical power
2. Turn on pressure switch? Plugged in? Check fuse/
breaker or motor overload.
3. Blown fuse
3. Replace blown fuse.
4. Breaker open
4. Reset, determining why problem happened.
5. Thermal overload open
5. Unplug and allow motor to cool before trying to
restart.
6. Shorted or open motor winding
6. Replace motor.
Motor hums but cannot run
or runs slowly
1. Low voltage
1. Check with voltmeter.
2. Unit is plugged into extension cord
2. Remove extension cord or use larger gauge
extension cord.
3. Shorted or open motor winding
3. Replace motor.
4. Defective check valve or unloader
4. Replace or repair.
Fuses blow/circuit breaker
trips repeatedly
1. Incorrect size fuse, circuit overloaded 1. Check for proper fuse, use time-delay fuse.
Disconnect other electrical appliances from circuit or
operate compressor on its own branch circuit.
2. Unit is plugged into extension cord
2. Remove extension cord or use larger gauge
extension cord.
3. Defective check valve or unloader
3. Replace.
Thermal overload protector
cuts out repeatedly
1. Low voltage
1. Check with voltmeter.
2. Clogged air filter
2. Clean filter (see Maintenance section).
3. Lack of proper ventilation / room
temperature too high
3. Move compressor to well ventilated area.
4. Unit is plugged into extension cord
4. Remove extension cord or use larger gauge
extension cord.
Air tank pressure drops when
compressor shuts off
1. Loose connections (fittings, tubing,
etc.)
1. Check all connections with soap and water solution
and tighten.
2. Loose drain valve
2. Tighten.
3. Check valve leaking
3. Disassemble check valve assembly, clean or replace.
Do not disassemble check valve
with air in tank; bleed tank first.
4. Check tank for cracks or pin holes
4. Replace tank. Never repair a damaged tank.
Excessive moisture in
discharge air
1. Excessive water in air tank
1. Drain tank.
2. High humidity
2. Move to area of less humidity; use air line filter.
Compressor runs continuously
1. Defective pressure switch
1. Replace switch.
2. Excessive air usage
2. Decrease air usage; compressor not large enough for
a requirement.
3. Air leaks
3. Check all connections with soap and water.
Compressor vibrates
Loose mounting bolts
Tighten.
Air output lower than normal
1. Broken inlet valves
1. Replace valve plate assembly.
2. Intake filter dirty
2. Clean or replace intake filter.
3. Connections leaking
3. Tighten connections.
MAINTENANCE /
REP
AIR
TROUBLESHOOTING
OPERA
TION
ASSEMBL
Y /
INST
ALLA
TION
SAFETY /
SPECIFICA
TIONS
GETTING ST
AR
TED
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