Compressor won't shut off / low pressure from regulator

[HolySheet!]

Hello,
I have a DeWalt D55168 compressor. Link below.

http://www.homedepot.com/p/DEWALT-15-Gal-Portable-Electric-Air-Compressor-D55168/100497924

Two problems:

1. The compressor will not shut off. It builds pressure to about 200 psi and blows the relief valve.

2. The pressure coming from the tank even when the tank has 200 psi is very low. It will barely run any air tool. I removed the hose out of the equation and hooked tools directly up to the valve on the compressor. Same problem, just enough pressure to spin my orbital sander, but you can stop the sander from turning with a finger tip.

Could it be a bad pressure switch and bad regulator? Will either one cause both problems?

Any ideas?


Thanks in advance.

 

[The Cobbler]

sounds like you have 2 problems, your pressure switch isn't shutting off the compressor, and the regulator .I'm assuming you did try adjusting the reg to increase the air pressure

did you buy this new? has someone fooled with the pressure switch in attempts to get more air pressure on the air line ?

 

[HolySheet!]

sounds like you have 2 problems, your pressure switch isn't shutting off the compressor, and the regulator .I'm assuming you did try adjusting the reg to increase the air pressure

did you buy this new? has someone fooled with the pressure switch in attempts to get more air pressure on the air line ?

I bought it new about 2-3 years ago. I have never adjusted anything on it. Would going in and cleaning / lubricating the parts help?

 

[highcarbon]

is the tank full of water? is the guage accurate ? is the relief valve really cracking at 200? what is the tank rated at ?

 

[md21722]

Could it be a bad pressure switch and bad regulator? Will either one cause both problems?

Normally the pressure switch senses the tank pressure and will allow the motor to cycle on and off. If the pressure switch is faulty or not sensing pressure correctly it can overrun the pump. As far as low air volume out of the tank, I would look to the regulator itself. Many of these packaged compressor regulators are small 1/4" NPT and cut 20 psi off the pressure to the tool to begin with even new out of the box. It sounds like the overpressure valve is working as designed. In some cases they can blow early but at 200 PSI it sounds right.

A good replacement pressure switch shouldn't cost more than $25-35. A good filter/regulator setup will likely cost 2-3X as much. I suggest taking everything apart for physical inspection before replacing parts. If you don't have a ball valve on the tank outlet it's a good time to install one.

 

[G_P]

Open the pressure switch and see if there is a diagram inside showing how to adjust it. It is possible that someone cranked the pressure up to try and make up for the bad regulator.

If the switch is bad, replacements are not very expensive and easy to change out. Just be sure to get one with the same size pipe threads as your current switch and if your switch has a built in unloader, make sure the new one has this as well.

As for the regulator, I would take it apart and see if there is any debris stuck in there that might be causing it to stick. Most likely scenario is that is has failed though. Same as the switch, they are not very expensive but make sure you either get one with the same size threads, or get one with bigger fittings and get a reducing bushing to adapt it to the output of the compressor.