Air compressor pilot valves, also known as unloader valves, control the motor cut-in and cut-out action on air compressors. When the pressure reaches the desired PSI, the pilot unloader valve opens, allowing the compressed air to “unload" into the tank; when the pressure drops too low, the valve closes, signaling the motor and pump to start up again to compress more air up to the right PSI.

Match an air compressor pilot valve with the PSI range of your compressor for optimal and safe operation. If you’re not sure which type of pilot unloader valve is right for your machine, talk to the helpful customer support staff here at Master Tool Repair. They’ll be happy to help you find the right valve.  

The how-to video below shows how to adjust a pilot unloader valve, or click on this link to view the downloadable .pdf instructions: