May 1, 2015

How to replace an air compressor check valve

By Lyle Weischwill
How to replace an air compressor check valve

This step-by-step repair guide gives instructions for replacing the check valve on an air compressor. The check valve stops compressed air from flowing back into the pump from the tank. If the check valve is stuck open, high air pressure from the tank flows back into the pump head. The high pressure in the pump head won’t allow the piston to move, and the motor can’t start. Replace the check valve with the manufacturer-approved replacement part.

Use these steps to replace the check valve on common Craftsman, Dewalt and Devilbiss air compressors.

Quick links
Tools required
Work gloves
Wrench Set
Repair difficulty
Time required
15 minutes or less
Repair difficulty
Time required
15 minutes or less
Replacing a check valve on an air compressor

This video explains how to replace the check valve on an air compressor.

Instructions

01.

Shut off the electricity and drain the air tank

Unplug the air compressor’s power cord from the wall outlet.

Pull the ring on the safety valve to drain all air pressure from the tank. Wear work gloves to protect your hands.

Unplug the power cord.

Unplug the power cord.

Drain the air tank.

Drain the air tank.

02.

Disconnect the pressure switch tube

Unscrew the pressure switch tube fitting and disconnect the pressure switch tube from the check valve.

Disconnect the pressure switch tube.

Disconnect the pressure switch tube.

03.

Disconnect the outlet pressure tube

Unscrew the outlet tube fitting and disconnect the outlet tube from the check valve.

Disconnect the outlet tube from the check valve.

Disconnect the outlet tube from the check valve.

04.

Remove the check valve

Unscrew the check valve and remove it from the tank.

Unscrew the check valve.

Unscrew the check valve.

05.

Install the new check valve

Thread the new check valve into the tank.

Tighten the check valve and align the fitting to connect the pressure switch tube.

Install the new check valve.

Install the new check valve.

06.

Reconnect the outlet tube

Reinstall the outlet tube on the check valve.

Reinstall the outlet tube.

Reinstall the outlet tube.

07.

Reconnect the pressure switch tube

Reinstall the pressure switch tube on the check valve.

Reinstall the pressure switch tube.

Reinstall the pressure switch tube.

08.

Restore power

Plug the compressor back in.

Plug the compressor in.

Plug the compressor in.

Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs should only be performed by a qualified technician.
Symptoms common to all air compressors

Choose a symptom to see related air compressor repairs.

Main causes: lack of electrical power, check valve failure, bad pressure switch
Main causes: rusted air tank, loose air tube fitting connections, bad check valve, leaky safety valve, bad tank drain valve
Main causes: bad safety valve, pressure switch failure
Main cause: faulty output air pressure regulator
Main causes: tank drain valve open or leaking air, leaky air tank, bad safety valve, worn pump seals, bad pump valve plate
Main cause: bad air tank pressure gauge
Main causes: loose air tube fitting connections, bad check valve, faulty safety valve, damaged or corroded air tank, bad air pump
Repair guides common to all air compressors

These step-by-step repair guides will help you safely fix what’s broken on your air compressor.

May 1, 2015
By Lyle Weischwill
How to rebuild an air compressor pump

If the air compressor won't fill the tank with compressed air, rebuild the pump using these steps in about 45 minutes.

Repair difficulty
Time required
 45 minutes or less
How to replace an air compressor pressure switch

You can replace a broken air compressor pressure switch in about 45 minutes.

Repair difficulty
Time required
 45 minutes or less
How to replace an air compressor check valve

You can replace a defective air compressor check valve in about 10 minutes.

Repair difficulty
Time required
 15 minutes or less
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