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.

Instructions

1. 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.

2. Disconnect the pressure switch tube

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

3. Disconnect the outlet pressure tube

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

4. Remove the check valve

Unscrew the check valve and remove it from the tank.

5. 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.

6. Reconnect the outlet tube

Reinstall the outlet tube on the check valve.

7. Reconnect the pressure switch tube

Reinstall the pressure switch tube on the check valve.

8. Restore power

Plug the compressor back in.