Dewalt d55275 shows 120 psi, but won't run air tools

SOURCE: low psi in reserve tank on a dewalt air compressure

This is a fairly common problem in small pancake compressors. I would start by making sure no air is escaping from the condensation drain valve on the bottom of the tank.

Next Pump it up as much as it will hold and turn it off. Listen for air leaks around the fitting on the bottom of the regulator that screws into the tank. These really need teflon tape and to be screwed in well.

Next check the regulator itself. These are rather inexpensive and don't last long when the compressor is used a lot. Also it doesn't take much of a bang when jostled around.

Is the regulator for tank pressure set correctly? Thump the glass covering the dial with your finger. Sometimes it sticks and you'll think it's set correctly when it isn't.

Lastly, check each connection for tightness with teflon tape. If all looks good, gamble about $20 on a new regulator. Odds are that's where the problem lies. This has happened to me a few times.

Marc Powers

• 146 Answers
• Posted on Oct 13, 2010

SOURCE: I have a dewalt D55168 air compresser. motor stays

Here is a parts diagram for the air compressor:

http://shoppingcart.msservicecompany.com/msservice_net/product_files/D55168/D55168_PL.pdf

There are a couple of things to look for on the air compressor.

You will need to see if the piston ring is damaged or if you have a broken reed on the valve plate.

These are typically the two most common problems with this model.

SOURCE: dewalt air compressor keeps running until pressure

The regulator switch/unloader is bad or out of adjustment. Perhaps though the gauge is faulty. 200 psi in a 120psi compressor is dangerous, don't run it until it is fixed!

SOURCE: air compressor starts up and

Any idea of HP rating? It doesn't take much compressor to trip a regular 15A breaker.

SOURCE: Dewalt D55168 air compressor runs until 95 psi and

If you have no leaks the first thing I'd check is the ring and cylinder for wear. The cylinder wear is usually pretty obvious, but if you can see light around the piston ring it's bad. The replacement part number is N038785. Also check to make sure no valves on the valve plate part number A09819 are broken or bent.