Official Hitachi air compressor parts

Troubleshooting tips for your Hitachi air compressor when it 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 air 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.

Common Hitachi air compressor repair parts

• Pressure switch. The pressure switch turns the air compressor on and off to regulate the tank air pressure.
• Regulator. The regulator controls air pressure from the tank to the supply hose.
• Safety valve. Attached to the manifold, the safety valve pops open to relieve excessive air pressure when the pressure switch fails to shut off the pump at the cut-out pressure setting.
• Tank drain valve. Fixed at the bottom of the air tank, the drain valve drains condensate water from the tank.
• Valve plate. Fixed above the cylinder, the valve plate controls air movement into and out of the cylinder to compress the air.