Air Compressor: Won't start

Check the electrical outlet for power. Reset the house circuit breaker if the electrical outlet is dead. If the electrical outlet works, shut off the compressor and bleed all the air from the tank. Flip the pressure switch control lever to the Auto position. If the pump starts when the tank is empty, then the check valve may be stuck open. The check valve prevents tank air from back flowing to the pump. A stuck-open check valve causes high pump head pressure, preventing the compressor from restarting. Test the check valve by allowing the compressor to fill the tank until the pump shuts off. Then pull the ring on the safety valve to bleed air out of the tank to reach the cut-in pressure, so the pressure switch attempts to restart the motor to refill the air tank. If the compressor won't start with air in tank, replace the check valve. If the compressor won't start with an empty air tank, replace the pressure switch if it isn't activating the pump motor. Replace the pump motor if it doesn't start when activated by the pressure switch.

air compressor

These repairs may help solve your air compressor problem

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
Read more
Replace the air compressor check valve

Replace the air compressor check valve

The check valve prevents tank air from back flowing to the pump. A failed check valve will apply high air pressure to the head of the pump preventing the motor from restarting once the tank has filled. If the motor starts when the tank is empty of air but won't restart when the tank is full, replace the check valve.

How to replace an air compressor check valve

If your air compressor won't restart after the tank fills, the check valve might be the problem. This DIY repair guide and video explain how to replace an air compressor check valve in less than 15 minutes.

Repair difficulty
Time required
 15 minutes or less
Read more
Replace the air compressor pump motor

Replace the air compressor pump motor

The pump motor spins the shaft that drives the compressor piston. Replace the pump motor if it doesn't run when activated.

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.