Boy, I’ve had a significant number of inquiries to the ASK Page of my compressed air information website, asking what might be the cause of their compressor not shutting off.
They know that there is a high pressure cut-off which is supposed to shut off the compressor motor when the pressure in the tank reaches that pressure level. They know there is a problem because their PRV (pressure relief valve) opens and starts to blow down the overpressure in their tank.
Number one: This is a very dangerous situation.
If your compressor’s PRV is blowing, don’t use the compressor until you get it fixed. Heaven forbid that the PRV failed, but if it did, your home compressor has now become very scar with the potential for fatal results.
Number two: If the compressor doesn’t shut off at the high pressure setting, the problem is likely that the pressure switch has failed. Don’t use the compressor until you get this replaced and the compressor shuts off at the right pressure.
Be careful! Overpressurized vessels can rupture with very unhappy results. Get the pressure switch changed out fast.