How to Replace an Air Compressor Pressure Switch

 

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This DIY repair guide explains how to replace the pressure switch on an air compressor. The pressure switch starts the pump motor as the tank empties and pressure drops to the cut-in pressure; the switch stops the motor when tank reaches the cut-out pressure.

Over time, the pressure switch wears out. If the pressure switch won’t start the pump when tank pressure drops below the cut-in pressure or won’t stop the pump when the tank reaches the cut-out pressure, replace the pressure switch with the manufacturer-approved replacement part.

This procedure works on common Craftsman, Devilbiss, Dewalt, Campbell Hausfeld and Porter Cable air compressors.

Repair difficulty:
     
Time required:

Less than 45 min.

Part Required

  • Pressure Switch

For manuals, repair guides, and specific part recommendations, enter your model number.

Tools Required

  • Work gloves
  • Wrench set
  • Nut driver set
  • Thread-sealing tape

Before you begin

Wear work gloves to protect your hands.

Instructions

 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.

Step 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.

Step 2: Remove the tank pressure gauge

Unscrew the tank pressure gauge and remove it from the pressure switch.

Step 3: Remove the pressure switch tube

Unscrew the pressure switch tube fittings from the check valve and pressure switch.

 

Remove the pressure switch tube.

Step 4: Remove the pressure regulator assembly

Unscrew the pressure regulator assembly and remove it from the pressure switch.

Step 5: Disconnect the wires

Remove the pressure switch cover.

 

Disconnect the two black wires from the pressure switch.

 

Disconnect the two green wires from the pressure switch.

 

Pull the two power cord strain reliefs off the pressure switch.

Step 6: Remove the safety valve

Unscrew the safety valve and remove it from the pressure switch.

Step 7: Remove the pressure switch

Unscrew the pressure switch assembly from the pipe connected to the tank.

Step 8: Install the new pressure switch

Apply thread-sealing tape to the tank pipe.

 

Screw the new pressure switch onto the tank pipe.

 

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

 

 

Step 9: Reinstall the safety valve

Apply thread-sealing tape to the threads of the safety valve.

 

Screw the safety valve into the new pressure switch and tighten firmly.

Step 10: Connect the wires

Remove the new pressure switch cover.

 

Using your digital photo as a reference, connect the wires to the new pressure switch.

 

Insert the power cord strain relief into the strain relief bracket.

 

Reinstall the pressure switch cover.

Step 11: Reinstall the pressure regulator

Apply thread-sealing tape to the pressure regulator connecting pipe threads.

 

Screw the pressure regulator and pipe into the new pressure switch and tighten firmly with the tank gage fitting facing up.

Step 12: Reinstall the pressure switch tube

Reconnect the pressure switch tube to the check valve and the pressure switch.

 

Tighten the fittings firmly.

Step 13: Screw the pressure gauge onto the new pressure switch and tighten the gauge firmly.

Step 14: Restore power

Plug the air compressor into the electrical outlet.