This page will provide you with our reader questions and responses about Dewalt D55146 and D55141 air compressors that do not start or shut off.

If you’re able to provide any advice, or have a question yourself, please drop a comment at the bottom of the page!

Table of Contents

Dewalt D55146 Questions & Responses

Dewalt D55146 Type 3 2.5 Gal Will Not Shut Off

Question:

by Jerrell
(Memphis)

It will not shut off at 180 psi anymore.

Pressure switch switch off/on (auto) selector dial has not been working for a while, would just leave it in the on/auto position then just unplug when done.

DeWalt 55146 air compressor

Been working a while this way but recently stop shutting off at 180 psi.

I would have to unplug power to get it to stop. It has gotten to 210 psi before I shut down.

While troubleshooting found that one of the hose coupler on the unit was leaking so replaced it, still got issue.

Since had I had a problem with pressure switch I replaced it.

Unit still will not shut off.

Next let all air out of tank then refilled till both pressure gauges showed 150 psi. Left sitting over night for 12-15 hours to see if had a leak any where. Both gauges still had 150 psi (one was showing 146 but felt this was ok).

Was going to spray all lines and fitting with soapy water to see if I had a leak but not sure if I need to now.

Anyway I am stuck as what my next troubleshooting steps should be. Can anyone help me out please?

Jerrell

Response:
by: Bill

When you use your multi-meter to check the power, is power still flowing from the pressure switch to the motor side even when the tank pressure rises past the normal cut out?

If yes, and assuming that the pressure switch is set to cut out at 185 PSI, then either the switch is pooched, or it’s wired wrong.

If the pressure switch is working, if it’s wired correctly, and if the pressure cut out is 185 PSI, when the tank pressure reaches +/- 5 PSI of 185 PSI the pressure switch will shift to non-passing (trip off), and power will no longer flow to the motor, stopping it.

At this point the tank pressure will no longer rise.

Response:
by: Doug in s.d.ca

That pressure switch (a21107) appears to be set to 200PSI.

The model appears to be a 4.5 (as opposed to 2.5) gallon tank.

The tank seems to be rated around 250PSI with a 225PSI safety.

The range on pressure switch is supposed to be +/-10%, so that’d be 180 to 220PSI, just short of the safety valve rating.

So, since replacing the pressure switch, have you let it run up to 220 or whatever the safety valve allows?

Response:
by: Jerrell

My bad typo it is a 4.5 gal unit

Yes tank rated at 200 psi

Unit best I remember, always shut off at 180 psi

But 180 or 200 it still does not shut off. One time I let it run up around 220 before unplugging. I do know for a fact that it has never run above 200 until recently.

Response:
by: Jerrelll

I am sure pressure switch is wired correctly.

Doing this from memory

Only 2 ground screws one each side of switch

One wire from both side of switch ttired together (idiot proof due to connector type)

2 other wires that are hard to get crossed due to length

BUT when you take about 15 pictures with iPhone prior to disconnecting it is hard to to wire switch wrong.

Have not checked power reading with meter but will check and update

Thanks for feedback

Jerrell


DeWalt D55146 Air Compressor Won’t Build Pressure

Question:

i have a dewalt compressor model # d55146. the motor runs good but does not build pressure. Whats up? jerry

Response:

Jerry, sorry you are having the problem with your compressor.

On these pages I posted a bunch of things that you could check to make diagnosis a lot easier for you, and my input, perhaps, more useful.

I have no idea what you checked after reading the page.

Could you maybe post a comment here to say what you have already checked, and more details about the state of the compressor when the pressure stops building, so I could help you zero in on the cause?


Dewalt D55146 Does Not Start

Question:
by: dan tiernan
(litchfield, nh)

i went to use my dewalt today and it would not start. I have had it for at lease eight years.

After further investigation, I notice grass and debris in the motor area.

I took the motor / compressor off the frame. then I took off the motor / compressor housing and found a significant amount of grass and debris in the area.

DeWalt 55146 air compressor
DeWalt 55146 air compressor

I removed then observed a severed wire attached to carbon brush.

I proceeded to solder the severed wired, but still had a problem. Then I measured the ac voltage on the switch off 0 on 115. then measured to input of motor off 0 on 115. but still motor does not start. any ideas?

Response:
by: Doug in s.d.ca.

Could easily be a brush problem. Did you actually check them?

If the rotor is exposed, there could be junk in there preventing contact with the armature, or they may just be shot.


DeWalt Oil-less D55146 Won’t Start

Question:
by: Mike Sessoms
(Charlotte,NC,USA)

DeWalt oil-less d55146 won’t start.

Turned it on one night and just heard a click. No start. Ran very well a couple of week ago. Only use at home for flat lawn mower tire/low pressure on my truck. Wanted to start using air tools to work on my car.

Can you help.

Thanks ,

Mike

Response:
by: Doug in s.d.ca

Sounds like maybe a breaker (probably on the motor) popped.

See the section here on why compressors won’t start and come back if you still have questions.

Response:
by: Anonymous

Capacitor or motor contacts-click sounds like capacitor but double check belt is on anyway

Dewalt D55141 Questions & Responses

Dewalt DD55141 Compressor Is Supposed To Stop Pumping at 150psi.

Question:
by: Daniel
(Washington)

It worked fine for about a year, until the warranty expired, then it started acting up. When the compressor hits 150psi, it keeps pumping, subsequently blowing the relief valve, and filling the tank again, over and over and over again. I looked for an adjustment screw, thinking it may have vibrated loose, but have yet to find one. Am I missing something? Thanks for an help!DeWalt 55141 air compressor

DeWalt 55141 air compressor

Response:

Your air compressor symptoms suggest a pressure switch failure.

The pressure switch should toggle the power supply to the air compressor motor to OFF when the pressure in the tank reaches the normal cut out pressure.

I wouldn’t use this compressor again until I replaced the pressure switch.

Dewalt Questions & Responses

Dewalt Compressor Won’t Stay Running

Question:
by: Jim
(TN)

Dewalt 4 gallon compressor wont stay running.

Theres no particular psi it stops at. It tries to restart after a moment or two but only turns the piston over once then keeps trying every few moments. Its definitely getting plenty of power.

Thanks, Jim

Response:

Jim, unplug the compressor and drain the air. Close the drain.

Pull the cover off the pressure switch (careful, live wires inside) and then start the compressor.

See how the switch reacts when the pressure gets to the normal cut out level or when the compressor just stops and tries to restart.

If is is the switch that is turning the power to the motor on and off, then I suspect it is the switch that is failing.


If you have any questions regarding Dewalt air compressors and them not starting or shutting off, please leave a comment below with a photo if applicable so that someone can help you!