I have a pressure switch on my well system that is supposed to cut in at 40psi and out at 60. A couple days ago, We lost all pressure for a moment then when the pressure restored the water was silty. When I checked the pressure switch I saw that it was cutting out at the max, 100psi. I opened it up and on the small screw (the cutoff set screw) the nut was up so no pressure was on the spring. Turning it further CCW would not losen the spring any more. How can I get the cut off pressure down?

The switch may have gone bad. Replace it.

Also when u replace it, clean the small tube that goes to it.

If u have a filter on system, replace that also.

Chuck