On Fri, 1 May 2020 19:09:30 -0500, dpb wrote:

I mentioned in a thread couple-three weeks ago "Learning Experience"
that a compressor kept running owing to relief valve failure that I'd
had the one here not cut off at pressure...

So, finally got new pressure switch and it acts same way...anybody think
of a reason the switch doesn't drop out at cutout pressure?

This is brand new switch as I just figured the old one had konked and
the contacts didn't look great and had 30+ yr service so hadn't done any
real looking at the switch itself.

The inlet pipe is not plugged, the air pressure drops and it will kick
in in synch with the gauge but just keeps on climbing past 125 cutout
when running...

Got me baffled...
Mabee it's set to 126 - or 150 -
Try resetting the pressure (or check your gauge - it may be reading
low)