[gto4evr]

Hello,

I'm working on my 80 gallon two stage compressor. I just replaced the pump with an HF head (that I hate) and decided to fix the secondary issue with the auto shut off valve. compressor turns on and runs up to 180 psi shut off, then restarts at 145. that part of it works. but around 5ish years ago I noticed that when it shut off at 180, the safety valve would engage that bleeds off the pressure through that little schrader valve and would bleed off pressure til it hit 150 before shutting off. I always assumed something was just bad on the switch. I had a different control switch that I changed out on the compressor when I replaced the pump head. same deal. it engages the safety and bleeds to 150. this second switch I had is identical to the small 20 gallon roll around compressor I have that shuts off at 175 and restarts at 145. on that compressor it shuts off and you hear just a momentary air bleed like it's testing the safety and then stops. (this is exactly how the big 80 gallon worked for the past 25 years for me). So I thought it odd that two switches are doing the same thing but that second switch I had was second hand from a scrapped compressor that I grabbed for safe keeping. so I bought a brand new switch. installed it and whaddyaknow....same damn thing. it shuts off at 180 and then bleeds the pressure down to 150 before popping closed. what the heck? I find it hard to believe 3 valves are all bad and doing the same thing but I see no way the original 80 gallon tank can be causing this? it shuts off at the correct pressure, it's just engaging the safety valve and bleeding all the pressure back out. so it can't be seeing a reason for the safety that I can understand. there's a small adjustment screw on the side of the head that I'd guess could be for adjusting the safety pressure? doesn't seem to have any affect by turning it one way or the other. (red arrow in picture) I know the main adjustment screw would be to adjust the 180 shutoff up or down.

I'm at a loss here. anyone have an idea what could be going on?