Dewalt d55140 won’t shut off at cut out - new pressure switch

by J. Woods
(Copperas Cove, tx)

Dewalt d55140 won’t shut off at cut out pressure even after installing new pressure switch.

I got a Dewalt d55140 compressor free from a friend. It wouldn’t shut off at the factory cut out pressure of 135psi, so I replaced the pressure switch. It still won’t shut off though and I’m not sure where to go from here. Would really appreciate any info you can guve me to point me in the right direction.

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Jul 20, 2018
Dewalt d55140 won't shut off
by: Doug in


I want to clarify a couple things...
You say it doesn't cut out at 135psi - what happens if you let run - does pressure stop increasing, or does it blow the safety valve, or ?

"the pressure gauge is going down very slowly"
This is the tank gauge? It will go down a bit as the hot air cools - but then does it stop or keep going down? All the way to zero? This could take all day, or longer. How long to stop or zero?


Jul 20, 2018
Its a type 1
by: Jeff Woods

Air connection ist at the back of the tank so i guess its a type 1. I just tried to find a leak by spraying the hose with soapy water, but didnt see any bubbles. Cant hear any hiss, but the pressure guage is going down very slowly.

Jun 13, 2018
Dewalt d55140 type 1 or 2?
by: Doug in

It should be noted on the ID decal.

If that is missing or illegible, the type 2 has an air connector at the right side of the tank at the top, while the type 1 is at the back of the tank.

Either way, the tube to pressure switch is probably leaking. If the tube is not split rotted, a gear clamp on it from the local big box store should fix it.

Let us know what you find, please. Good luck.

Jun 12, 2018
Not sure
by: J Woods

How can I tell what type it is?

Jun 09, 2018
A type 1 or 2 Dewalt d55140 pressure switch?
by: Doug in

And, if there's a tube to it, check that it's not leaking.

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