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18—ENG
CAUSE CORRECTION
PROBLEM
TROUBLESHOOTING GUIDE
PERFORMING REPAIRS MAY EXPOSE VOLTAGE SOURCES, MOVING PARTS OR COMPRESSED AIR
SOURCES. PERSONAL INJURY MAY OCCUR. PRIOR TO ATTEMPTING ANY REPAIRS, DISCONNECT
POWER SOURCE FROM THE COMPRESSOR AND BLEED OFF ALL TANK AIR PRESSURE.
Excessive tank pressure - safety
valve pops off (units with ON-
AUTO switch)
Pressure switch “cut-out” too high.
Contact Service Center to check and adjust, or re-
place switch.
Pressure switch does not shut off motor
when compressor reaches “cut-out”
pressure.
Move the pressure switch lever to the "OFF" position.
If the outfit doesn’t shut off, and the electrical contacts
are welded together, replace the pressure switch.
See "Wiring of Compressor Units"
Excessive tank pressure -
safety valve pops off (units with-
out ON-AUTO switch).
Pressure switch does not shut off motor
when compressor reaches "cut-out
pressure".
Incorrect wiring connections.
Pressure switch must be replaced.
See "Wiring of Compressor Units"
Continuous air relieving from
pressure switch release valve
after shut off.
Operate safety valves manually by pulling on ring. If
a valve still leaks, it should be replaced.
Air leak from safety valves. Possible defect in safety valves.
There is no oil in the compressor.
Squealing sound.
Loose belt.
Adjust belt tension. (See Belt Replacement.)
Add oil. (See Oil-Checking and Changing)
Air leaks at fittings or hose.
Tube fittings are not tight enough.
Tighten fittings where air can be heard escaping.
Check fittings with soapy water solution. DO NOT
OVER-TIGHTEN.
Air leaks at or inside check
valve.
Defective or dirty check valve.
A defective check valve results in a constant air leak
at the pressure release valve when there is pressure
in the tank and the compressor is shut off. Remove
and clean or replace check valve. DO NOT OVER-
TIGHTEN.
Air leaks at pressure switch re-
lease valve during running.
Defective pressure switch release
valve.
Remove and replace the release valve.
Defective check valve. See "Air Leak at Check Valve."
Air leaks in air tank or at air tank
welds.
Defective air tank.
Air tank must be replaced.
DO NOT DRILL INTO, WELD, OR OTHER-
WISE MODIFY AIR TANK. IT WILL WEAKEN.
THE TANK CAN RUPTURE OR EXPLODE.
Incorrect wiring connections.