Announcement

Announcement Module
Collapse

How To Post Images

Want to know the how to upload images to your posts? Image Posting Tutorial
See more
See less

Compressor builds pressure even when off

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Compressor builds pressure even when off

    I have a Ridgid 4.5-gallon, oil-free, twin-stack compressor that I only occasionally use. I keep it in my air-conditioned, heated, and dehumidified shop.

    Anyway, after I bleed off the pressure the thing seems fine, but then, the next day I will pull on the air-bleed valve and more air comes out. Not a lot, but some. I can do this once a day, day after day (even up to a week) and I still get a puff of air every time I pull that air-bleed valve.

    I have tilted the unit back and run it to clean out any moisture via the moisture-bleed valve in back and so I am pretty sure the tanks are reasonably dry inside. No water runs out of the moisture-bleed valve when I purge the thing, even if I tilt it back enough for any moisture settled in the bottom to be blown out of that moisture-bleed valve.

    What is generating small amounts pressure in this turned-off compressor? Could a small amount of rusting inside of the tanks generate gas pressure? I want to minimize rust in the tanks if I can help it.

    Howard Ferstler

  • #2
    Re: Compressor builds pressure even when off

    The only thing I can think of is if the hose is hooked up and has pressure in it and the regulator is letting some air leak back into the tank.

    or you are on the verge of creating perpetual motion,
    Push sticks/blocks Save Fingers
    ~~~~~~~~~~~~~~~~~~~
    "The true measure of a man is how he treats someone who can do him absolutely no good."
    attributed to Samuel Johnson
    ~~~~~~~~~~~~~~~~~~~
    PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

    Comment


    • #3
      Re: Compressor builds pressure even when off

      I've not a clue if this is part of what is happening or not but possibly what you're experiencing has something to do with the changes in atmospheric pressure. I just thought I'd throw out that WAG.
      Teach your kids about taxes..........eat 30 percent of their ice cream.

      Comment


      • #4
        Re: Compressor builds pressure even when off

        couple of things come to mind

        with a closed tank, you have a potential for temperature change that will create a change in pressure and volume.

        as the temp goes up it will create expansion and pressure.

        of course keeping the drain plug open, will not allow this to happen, but could create a potential for rusting as it will introduce oxygen/ air.

        rick.
        phoebe it is

        Comment


        • #5
          Re: Compressor builds pressure even when off

          What Rick said. Best to drain off water and close the tank with air in it. Been doing that for 40 years and no issues with rust in tanks and it is thought to have less stress on the tank as it is not expanded and contracted constantly, going from empty to full. The regulator may be the issue.Take the hose off and see. I have cleaned and rebuild mine as contaminants can get in if you have the regulator before your filter. If I have the filter in front of the regulator, no issues.

          Comment


          • #6
            Re: Compressor builds pressure even when off

            My bet is that it's thermal expansion of the air inside the tank(s) causing this. When you open the drain just open it enough so any moisture comes out. If you rapidly discharge air from a tank the temperature drops. Once stopped and temperatures stabilize the pressure will rise some. You might try leaving the drain open for say 1/2 - 1 hour and then close it.

            Comment


            • #7
              Re: Compressor builds pressure even when off

              Many thanks for all of those responses. It may just be atmospheric changes in pressure, because on some days when I open the valve there is a hiss and on other days there is none. This would relate to barometric shifts, I think.

              There are no hoses connected to the unit when it is not being used, so that kind of back pressure would not be an issue.

              Whatever, the pressure differences are small and I doubt that the tanks are being stressed. I was just concerned that maybe rust-forming activity in the tanks was causing some kind of low gas pressure or partial vacuum. The tanks are pretty thoroughly drained and no water runs out of the drain plug, rusty or otherwise.

              All in all, it is a good compressor that works fine for the small-project work I have done. Most of this involves reinforcing my attic with additional timbering (we live in a hurricane-prone area) and adding more (and better) nails to the siding on the house to stiffen the walls that way a bit. Used a Ridgid framing nailer. Also have some Campbell-Hausfeld nailers: framer, finishing, and pin, all picked up as a group at Lowe's, and cheap. I think that C-H actually built the Ridgid compressor, actually.

              Howard Ferstler

              Comment


              • #8
                Re: Compressor builds pressure even when off

                Don't forget, the "Hiss" works both ways... if the temperature in the tank is colder than the room temperature or there's been rise in barometric pressure since the tank was shut off, that hiss could be a vacuum inside the tank too.

                However, I've never noticed it with any compressor that I've had, perhaps because I only use the drain valve on completion of a project and don't crack open the drain valve before I use the unit again.

                CWS

                Comment

                Working...
                X