Review on 💨 240V Air Compressor Pressure Switch Control Valve with Adjustable Range of 90-120 PSI by Meech Elliott

First of all, it flows through the seal. I installed it and turned it on to 40psi, turned it off and it leaked. Spraying with soapy water can reveal leaky seals. I have to remove it and tighten the four small screws and reinstall. There are no more leaks. Then the power was still on at 125 psi. It was scary. So I set the screw to the minimum and cycled the air on and off many times to set the cut off at 115psi. My old switch is the same and I took it apart to see what went wrong. It was a seal that looked like a bicycle tire, worn and torn. If your rear derailleur is leaking (high hiss), take it apart and replace the seal (a bike tire will do) and you can fix it without buying a new one. I wish there was some sort of manual for setting the pressure in the kit.