I have an air compressor that reaches the set air pressure of 90 pounds, however, the compressor itself does not shut off and continuously sucks air.

Is this an issue with the regulator? … says John (MS)

D55146 1.6 Hp Continuous, 200 Psi, 4.5 Gallon Compressor

D55146 1.6 Hp Continuous, 200 Psi, 4.5 Gallon Compressor

I’m assuming it’s most likely a valve of some sort. I looked at a parts list and it looks like the manifold assembly is discontinued, what us the OEM equivalent?

Thanks ahead of time


DeWalt 55146 won’t shut off
by: Bill

If the air pressure in the tank gets to the normal cut out pressure setting, and the compressor does not shut off, then that typically is a problem with the pressure switch.

If the pressure in the tank never gets to the normal cut out, and the compressor runs and runs, then that typically points to the pump being the problem.

Since this compressor normally has a cut out setting of 200 PSI, and I infer from your post that the pressure is only getting to the 90 PSI level, you most likely have a compressor pump problem.

If I have misinterpreted what you have written, please clarify with a comment here.


DeWalt 55146 does not shut off
by: Doug in s.d.ca

To put it another way, does the tank gauge also stop rising at 90? That’s the one on the left.

If it keeps rising, let it go until it stops increasing – around 200 is normal. If it doesn’t then shut off, you have a problem. If it does stop, then it’s operating normally.


by: John

Thanks for the response and I’m sorry for the delay. The pump continues to run but the needle stops at the set pressure of 90 psi. I checked this model a little more an other pumps and I see the pressure switch is a common issue as I see is suggested in the response.

I ordered a pressure switch for the pump but after ordering I saw there is a valve of some sort as well (brass not polymer like in the pressure switch).


DeWalt 55146
by: Bill

John, if the tank gauge stops at 90 PSI, and the compressor continues to run, as it says below, it’s not likely the pressure switch, but the pump itself that is the problem.

If you’ve already ordered a pressure switch I’ll bet you end up with a spare, as the one you replace may be fine.

I’m sorry, I don’t understand “I saw there is a valve of some sort as well (brass not polymer like in the pressure switch). “. Is there a question here?


by: John

Based on what you are saying it looks like I’m going to have a spare. But regarding the brass valvle, I watched a rebuild for this model and they cited the brass valve as a potential issue as well. I’ll take the input from the people that know more than i.

I guess it may be better to invest in another compressor if it’s cost prohibitive.


DeWalt 55146 valve
by: Bill

John, it would be good if you could tell me the name of the valve, or what they call it.

If it’s the unloader valve, typically there is either one on the side of the pressure switch (may be plastic but more often brass) or, if the switch has the unloader internally, the line will insert into a quick fitting on the bottom of the pressure switch.

This valve – if the unloader, will have nothing to do with the run on compressor UNLESS the tank check valve is compromised. Then, air will leak out of the tank continuously when the compressor stops.

Please take the time to read about the various compressor components that are explained in great detail on this site, along with the many troubleshooting pages which are written for folks just like you; struggling with an air compressor problem.


by: John

First thank you for the comments and help. I did replace the pressure switch and I also looked closer and realized there regulator was leaking. I was able able to clean the parts and lube the O rings and no leaks.

The compressor now reaches 210 and shuts off.