Craftsman 921.153120 owner manual Troubleshooting Guide, Problem Possible Correction

Troubleshooting Guide

WARNING The air compressor should be turned off and unplugged from the power source before any maintenance is performed as well as the air bled from the tank and the unit allowed time to cool. Personal injuries could occur from moving parts, electrical sources, compressed air, or hot surfaces.

PROBLEM POSSIBLE CORRECTION

Air leaks at the check valve or at the pressure relief valve.

A defective check valve results in a constant air leak at the pressure relief valve when there is pressure in the tank and the compressor is shut off. Drain the tank, then remove and clean or replace the check valve.

Air leaks between head and	Be sure of proper torque on head bolts. If leak remains, contact a service technician.
cylinder.

Air leak from safety valve.

Operate the safety valve manually by pulling on the ring. If the valve continues to leak when in the closed position, it should be replaced.

Pressure reading on the	If there is an excessive amount of pressure drop when the accessory is used,
regulated pressure gauge	replace the regulator.
drops when an accessory is
used.	NOTE:
	Adjust the regulated pressure under flow conditions (while accessory is being used).
	It is normal for the gauge to show minimal pressure loss during initial use of the
	tool.
Excessive tank pressure.	Move the Auto-On/Off lever to the Off position. If the unit doesn’t shut off, unplug it
	from the power source and contact a service technician.
Motor will not start.	Make sure power cord is plugged in and the switch is on. Inspect for the proper size
	fuse in your circuit box. If the fuse was tripped, reset it and restart the unit. If
	repeated tripping occurs, replace the check valve or contact a service technician.
Excessive moisture in the	Remove the water in the tank by draining after each use. High humidity
discharge air.	environments will cause excessive condensation. Utilize water filters on your air
	line.
	NOTE:
	Water condensation is not caused by compressor malfunction. Be sure the
	compressor’s air output is greater than your tool’s air consumption rate.
Air leaks from the tank body	Never drill into, weld or otherwise modify the air tank or it will weaken. The tank can
or tank welds.	rupture or explode. Compressor cannot be repaired. Discontinue use of the air
	compressor.

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