17
TROUBLE SHOOTING CHART FOR COMPRESSOR
WARNING
Always disconnect unit from power supply and relieve all pressure from air tank before performing any
maintenance. “Tag Out” or “Lock Out” all power sources. Failure to do so may result in equipment damage or
injury.
Never operate unit without belt guard in place.
Never use gasoline or flammable solvent on or around compressor unit. Explosion may result.
Troubleshooting Chart
Symptom Possible Cause(s) Corrective Action
Motor will not start.
1. Main switch and fuses open.
2. Starter heater coils open.
3. Starter tripped
4. Defective pressure switch-
contacts will not close
5. Low voltage.
1. Check all fuses and switches. Check
for loose or faulty wires.
2. Check overload relay in starter.
Reset starter.
3. Reset starter. If starter trips
repeatedly, have electrical system
inspected by an electrician.
4. Repair or replace pressure switch.
Warning – Relieve tank pressure
before servicing.
5. Check with voltmeter. Be sure
voltage corresponds to unit
specifications.
Starter trips repeatedly. 1. Improperly adjusted pressure switch.
2. Faulty check valve.
3. Incorrect fuse size or magnetic starter
heaters.
4. Low voltage.
5. Defective motor.
1. Adjust or replace.
Warning – Relieve tank pressure
before servicing.
2. Clean or replace
Warning – Relieve tank pressure
before servicing.
3. Be sure that fuses and heaters are
properly rated.
4. Check with voltmeter. Be sure
voltage corresponds to unit
specifications.
5. Replace motor.
Tank pressure builds up slowly. 1. Air leaks.
2. Dirty air filter.
3. Defective compressor valves
1. Tighten fittings.
2. Clean or replace.
3. Install new valve plate assembly.
Tank pressure builds up quickly. 1. Excessive water in tank. 1. Drain tank.
Discharge pressure relief valve pops
off while compressor is running.
1. Wrong pressure switch setting.
2. Defective ASME relief valve.
1. Adjust to correct setting.
2. Replace valve.
Warning – Relieve tank pressure
Compressor will not unload 1. Wrong pilot valve setting.
2. Defective pilot valve.
3. Lack of air to pilot valve..
1. Adjust to correct stting
2. Replace pilot valve.
3. Open needle valve to pilot valve.
Excessive belt wear. 1. Pulley out of alignment.
2. Belts too tight or too loose.
1. Realign motor pulley.
2. Adjust belt tension.
Compressor runs hot. 1. Improper flywheel rotation
2. Defective compressor valves.
3. Dirty air filter.
4. Dirty cylinder and/or intercooler.
1. Check for correct rotation.
(Counter clockwise when viewed
from drive side.
2. Install new valve plate assembly.
3. Clean or replace.
4. Clean cylinder fins and/or intercooler.
Interstage pressure relief valve pops off. 1. Defective compressor valves. 1. Install new valve plate assembly.
Excessive oil consumption. 1. Dirty air filter.
2. Wrong oil viscosity.
3. Oil leaks.
4. Worn piston rings.
5. Scored cylinder
1. Clean or replace.
2. Refill with proper viscosity oil.
3. Tighten bolts. Replace gaskets.
4. Replace rings.
5. Replace cylinder.
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