I have a craftsman air compressor. It's about 20 years old, but for many years now, if I let it run on it's own, it will always blow the pressure relief valve. I don't need a lot of volume, so I monitor it, turning on/off manually as needed. There must be an issue with the pressure switch.

Are compressor pressure switches adjustable or repairable?

  • That depends on the particular pressure switch. Some are adjustable. I'd bet that very few are (economically) repairable. They are (AFAIK) all replaceable.
    – Ecnerwal
    Feb 12, 2021 at 3:35
  • Yes, the pressure switch should be a service part. You can either get the book and get an official Sears part, or any equivalent unit from Grainger or McMaster-Carr will probably also suffice. Feb 12, 2021 at 7:53
  • that pressure relief valve will only blow so many times, and lord help you when it doesn't.
    – dandavis
    Feb 12, 2021 at 16:40
  • It depends on which part you are talking about. There is a main pressure safety valve and a pressure relief valve that vents pressure so the motor can start. The safety’s are not usually adjustable (some are but many come with the adjustment safety wired). The pressure relief on the on off is usually adjustable and this allows the motor to start unloaded. Some may vent for a second or 2 and that is by design.
    – Ed Beal
    Feb 15, 2021 at 16:30


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