If it is no longer keeping the air in the tank due to it leaking then the tank full of compressed air flows out of the unloader valve too until the tank pressure drops to the cut in pressure.
Air compressor leaking check valve.
When you are not working with the compressor air should not leak from the tank of the compressor.
The air compressor check valve can be found on almost any compressor out there check valves are used for example on reciprocating piston compressors rotary screw compressor and scroll compressors.
Air continuously leaks out of the unloader valve on your air compressor and this is a problem.
Also helping understand what check valve t.
The check valve is an important part of any air compressor.
The tank check valve an image of one which is shown below is typically located where the air line from the pump head enters the compressor air tank.
Well if air continuously leaks out of the unloader valve then the compressor tank is emptying and the compressor needs to restart to replenish the air in the tank to get back up to cut out pressure so it can stop on its own.
A video on air compressor check valves telling information you need to know about replacing them and installation.