compressor is leaking air from the PSI adjustment knob valve

[mds33200]

I have a compressor and it keeps kicking on so I knew it had a leak. As I got closer to the compressor to check for the leak I could hear a hissing sound coming from the PSI adjustment knob. I unscrewed the knob (which should have reduced the outgoing psi to zero) but when I removed the rubber plunger (the piece that connects to the metal spring inside the adjustment knob) I could hear air exiting the valve.

Air appears to be leaking on the right side if the pipe, behind a metal plate. I drew a red X on the photo where the air seems to be coming from.

I put the unit back together by inserting the plunger and the spring, and after doing that it appeared to be fixed, then about 10 minutes later the hissing sound goes off again. I did this several times but the fix only lasts about 10 minutes at most.

Is there any trouble shooting for this? Or do I need to purchase a new controller / PSI adjustment pipe?

 

[gizardlizard]

The diaphragm in the regulator is shot. Pin hole or dry rot age tear. Replace the regulator. You can look for a rebuild kit but doubt you’ll find one.

 

[no704]

Just get an aftermarket regulator.

 

[The Cobbler]

check the o ring around the piston , look for pin holes in the piston. I have actually replaced the piston in a regulator rather than replumbing everything. they seem to be fairly standard . BTW, I'm calling it a piston but I mean the disc that adjusts the pressure

 

[Elyat]

I had same issue. Dismantled and cleaned regulator and put a light Vaseline coat on o-ring and it now works great.

 

[Citation]

OP, when does it leak? The side you indicated with the X is the outlet side of things. When you reduce pressure that side should vent. Reducing pressure via the regulator in most cases will result in the regulator venting air out of the hoses etc as it reduces pressure in the lines. Based on where you put the X, if the system is leaking there, especially after you have removed the knob, then you have air in the lines that for what ever reason is leaking down slowly.

This looks like almost the same setup. Perhaps these instructions can help

Dewalt Air Compressor DWFP55126 2016 Regulator Rebuild

Use this guide to rebuild or repair a faulty...

www.ifixit.com

That said, a new regulator manifold like that one is cheap and could be replaced with something that looks different. For example, here is a similar (but cheaper) version

https://www.amazon.com/dp/B06XBVPGPX/?tag=atomicindus08-20

and a PC model.

OEM Porter Cable Compressor Manifold Assembly. [N246884] | Ships Today | Fix.com

Porter Cable Compressor Manifold Assembly. N246884 - Sourced directly from Porter Cable, this Manifold Assembly is an OEM approved replacement part for sele...

www.fix.com

A better option would be to replace the whole thing with a T fitting, some connectors and a new regulator. You already have the blow off valve so just a short section of pipe from the compressor then a T with the blow off valve on one side and a new regulator on the other. Then connect your female coupler (or a T and two couplers) to the outlet.

https://www.lowes.com/pd/Kobalt-Mini-Air-Regulator/50126536

Lots of options just so long as you have a blow off valve.

 

[metalmagpie]

Check valve?

 

[Citation]

Check valve?

The check valve would result in air leaking from the tank back to the pump. If this pump has an typical unloader valve it would appear that the unloader valve is continuously leaking when the pump is off.

 

[jbtvt]

I had same issue. Dismantled and cleaned regulator and put a light Vaseline coat on o-ring and it now works great.

Better if with silicone grease on rubber parts, Oatey plumbing, caliper grease etc. Petroleum grease will shorten the lifespan

 

[scooby074]

Id just remove that factory junk and get an aftermarket regulator like a Milton, Watts etc... If you have a surplus store nearby I bet there would be a decent one there for cheap! Even new, a small reg, like youd need wouldnt be that expensive.