Air Compressor: Safety valve keeps popping open

If the safety valve trips at operating pressure or well below the relief set point, replace the safety valve because it's broken. If the tank is over pressurized, the pressure switch isn't shutting off the motor when the air tank fills to the cut-out pressure. Move the pressure switch lever to the off position. If the compressor continues to run, replace the pressure switch because the switch isn't shutting off the compressor motor. If the compressor shuts off when you move the pressure switch lever to the off position, pull the safety valve ring and release all air from the tank. Switch the pressure switch lever to the on position and allow the tank to fill. If the compressor doesn't shut off when the air tank fills to the cut-out pressure, replace the pressure switch because the switch isn't shutting off the compressor motor when tank pressure reaches the cut-out pressure.

air compressor

These repairs may help solve your air compressor problem

Replace the air compressor safety valve

Replace the air compressor safety valve

The safety valve pops open to relieve excessive air pressure if the pressure switch fails to shut off the air compressor at the cut-out pressure setting. Replace the safety valve if it leaks or pops open at normal operating pressure.

Replace the air compressor pressure switch

Replace the air compressor pressure switch

The pressure switch turns the air compressor pump on and off to regulate tank air pressure. If the compressor isn't cycling on and off to fill the tank, replace the pressure switch.

How to replace an air compressor pressure switch

If your air compressor won’t shut off after reaching full cut-out pressure or won’t start again after tank pressure drops, the pressure switch might be the problem. The step-by-step repair guide and video explain how to replace an air compressor pressure switch in less than 45 minutes.

Repair difficulty
Time required
 45 minutes or less
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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
Articles and videos common to all air compressors

Use the advice and tips in these articles and videos to get the most out of your air compressor.

May 1, 2015
Air compressor common questions
By Sears PartsDirect staff

These answers to common questions can help you make the most of your air compressor.

April 24, 2015
How to reduce air compressor noise
By Sears PartsDirect staff

Find out how to reduce air compressor noise.

April 22, 2015
The unseen dangers of air compressors
By Sears PartsDirect staff

Learn about the possible dangers associated with using an air compressor and how you can reduce the risks of property damage and personal injury.