by marshall
(nikes ohio usa)
Changed out safety switch with new part ordered thru ereplacements
compressor will not shut off at preset 150 psi. Have to manually shut off so it wont blow what else do I have to trouble shoot

Is it possible regulator may be problem?
Cant regulate tool pressure without it leaking?
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Hello Marshall. Since I cannot see the pressure switch that you ordered, I cannot tell is the pressure settings are adjustable. If they are, then that may be the issue. When you talk about the preset 150 PSI, I am assuming that was the normal cut out pressure setting of the previous switch before it went south?
When you say that the compressor won’t shut off, and you are afraid it will blow, what I surmise from this is that the tank pressure has not reached the cracking pressure of the PRV that’s almost always on a pressure vessel. How high did you let the pressure get to before you shut it down. See the PRV page, make sure yours is working, and let your air compressor run up an extra 20 PSI or so over the normal cut out to see if the pressure switch is just out of setting by a few PSI. If, for example, it shuts off at 158 PSI instead of the 150 PSI you normally had, this likely won’t be a problem for the compressor or for safety. If the PRV lets go, though, then the pressure switch definitely needs work.
“is it possible regulator may be problem ” no, if you are talking about the air regulator, it has no effect on the pump or the tank pressure. It only affects the downstream flow to your air tool. If the regulator vents air when you turn the pressure down, that’s normal. If, after setting your downstream pressure – below the tank pressure – and after a while air keeps blowing out of the air regulator, then it’s leaking and needs rebuilding or replacing, assuming that it is installed in the correct, flow path, orientation. See the regulator page for details.
Bill
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