actual pressure switch psi......

Well since i got my 110 / 150 pressure switch from horn blasters , it always kicks on at 110… but off at 140… I know its not the gauge either cause i have 2 gauges (one on tank , one inside truck)

I never thought to question this figuring it will loosen up and bocome 150, but now ive had this thing for probably a year and its still 140. :mad:

Anyone else have a problem like this?

my old pressure switch used to go to about 192ish for some reason. I believe the figures are ±5%. Anyways I replaced the switch and the new one I got goes to 200 every time… i’d replace it if you want to get that extra 10

As long as it is turning off, it is doing its job. The reason the pressure switch doesn’t cost $150 is because it is mass produced. Like most gauges, these are parts - not precision instruments. Instruments cost far more to produce because the tolerances are far tighter.

Pressure switches can have as much as a 5-7% swing in either direction… Meaning tolerance can be as low as:

150 / .93 = 139.5 (PSI)

any chance viar makes the grey box waterproof style switch but in like a 150 on 180 off …?

i use to have one of these on my old setup but it wasnt the grey box style…


Grey box sounds like it could be a “Square D” pressure switch. If there’s a big “S” on top, it’s a “Square D”.