Compressor Relief Valves?????
RSS | Subscribe | Contact Us | Advertise | About Us
Results 1 to 19 of 19
  1. #1
    Join Date
    Dec 2018
    Posts
    1,963

    Compressor Relief Valves?????

    Hey...…….I'm in the middle of some driveline work, and using the compressor to run tools.

    For about half a year, my compressor has started to leak down when not in use. It always held air for long periods on non-use. Then it started draining down within a few days.

    Fast forward to about 3 weeks ago...………….It quit leaking down...…….Cool says me...……

    But now the dam thing starts squeaking (at least I thought it was a belt squeak) when it comes up to 175psi...…..and it runs on without shutting down.

    The squeaking is at the top of the compressor, not down on the side where the shutoff switch/pop off valve is.

    Is there any way to check the valves at the top of the compressor cylinders???????? Dunno if soapy water will work, it's pretty hot on top of the cylinders, and breezy, what with the cooling fan running a few inches away I can't check for a leak when it's not running now, since it started holding air again...……..unless I just shut it down before it fills, or when it starts squeaking...…………….

    Hell, I might have answered my own question...…….GEEZ

  2. #2
    Join Date
    Dec 2008
    Location
    Lockhart,Tx (BBQ capitol of the world)
    Posts
    998

    Re: Compressor Relief Valves?????

    Sounds like a head gasket leak like the old Harley panheads and shovelheads used to do.

  3. #3
    Join Date
    Apr 2006
    Location
    Soda springs,Id
    Posts
    4,790

    Re: Compressor Relief Valves?????

    See if you can jerry rig an airtight connection to the intake side and put air pressure to it while it's stopped.
    Mike
    Ol' Stonebreaker
    "Experience is the name everyone gives to their mistakes"
    Hobart G-213 portable
    Miller 175 mig
    Miller thunderbolt ac/dc stick
    Victor O/A setup
    Makita chop saw

  4. #4
    Join Date
    Sep 2013
    Location
    central Wis.
    Posts
    4,290

    Re: Compressor Relief Valves?????

    Without knowing what compressor you have it's a guess. If it has a centrifugal governor, there is a shrader valve inside a sleeve which may not be sealing. If a pressure switch, it may not be sending air to the head to signal shutoff, and it may be belt squeal.
    Miller xmt304, Miller S22 p12, Miier Maxstar SD, Miller 252 w 30A, Miller super32p12, Lincoln Ranger 9, Thermal Arc 181I with spoolgun, Hypertherm 10000 ,Smith torches. Esab 161lts miniarc.

  5. #5
    Join Date
    Dec 2018
    Posts
    1,963

    Re: Compressor Relief Valves?????

    Name:  compressor1.JPG
Views: 459
Size:  217.0 KB

    Name:  compressor2.JPG
Views: 457
Size:  209.0 KB

    Name:  compressor3.JPG
Views: 461
Size:  214.2 KB

    My first thought was belt squeal, but belts appear tight. Hard to feel with the stupid safety cage.\\

    Like I say...…………………..it quit leaking down, and the squealing started (shrug) Now it squeals, and won't shut down at pressure. I'm thinking it might not be a squeal, but air escaping from one of the pop off valves. Didn't get a chance to look at it yesterday, and won't today.

  6. #6
    Join Date
    Dec 2013
    Posts
    1,378

    Re: Compressor Relief Valves?????

    Sounds like your pressure switch then. Original leak down from the switch or related piping maybe.
    ---Meltedmetal

  7. #7
    Join Date
    Dec 2018
    Posts
    1,963

    Re: Compressor Relief Valves?????

    Quote Originally Posted by Meltedmetal View Post
    Sounds like your pressure switch then. Original leak down from the switch or related piping maybe.

    It reaches 175psi (the proper setting for switch), then starts squealing, doesn't pass 175psi, doesn't shut down, but keeps on running while squealing.

    Could the top pressure in the cylinders cause the belts to slip when it reaches top pressure?

    The compressor drive wheel still turns, it doesn't stall when it squeals.

  8. #8
    Join Date
    Jun 2011
    Location
    Aiken SC area
    Posts
    1,153

    Re: Compressor Relief Valves?????

    Check the contacts in the starter with the power off, see if the contacts are welded together from arcing thus the reason it keeps running. Next, the pressure switch contacts not releasing when reaching preset due to being welded together from arcing, or possibly an obstruction in the pressure lines. Bob

  9. #9
    Join Date
    Dec 2008
    Location
    Lockhart,Tx (BBQ capitol of the world)
    Posts
    998

    Re: Compressor Relief Valves?????

    Those relief valves are not proportional, they are popoff valves.
    If any of them ever opened you would know it!
    They are probably not the source of the squeal but anything is possible!

  10. #10
    Join Date
    Dec 2013
    Posts
    1,378

    Re: Compressor Relief Valves?????

    Quote Originally Posted by farmersammm View Post
    It reaches 175psi (the proper setting for switch), then starts squealing, doesn't pass 175psi, doesn't shut down, but keeps on running while squealing.

    Could the top pressure in the cylinders cause the belts to slip when it reaches top pressure?

    The compressor drive wheel still turns, it doesn't stall when it squeals.
    Watch that pressure for obvious safety reasons. Maybe try your mechanics stethoscope to listen to the relief valves. I still suspect the pressure switch as it should shut off.
    ---Meltedmetal

  11. #11
    Join Date
    Apr 2006
    Location
    Soda springs,Id
    Posts
    4,790

    Re: Compressor Relief Valves?????

    I think the reason it keeps running after reaching 175 is a pressure switch problem. The pressure relief valves must be working else it would continue pumping past 175. One easy way to find if the belts ares slipping is, with a spray bottle of water, squirt the belts while it's squealing.
    Mike
    Last edited by mla2ofus; 04-12-2019 at 10:03 AM.
    Ol' Stonebreaker
    "Experience is the name everyone gives to their mistakes"
    Hobart G-213 portable
    Miller 175 mig
    Miller thunderbolt ac/dc stick
    Victor O/A setup
    Makita chop saw

  12. #12
    Join Date
    Sep 2013
    Location
    central Wis.
    Posts
    4,290

    Re: Compressor Relief Valves?????

    That is a centrifugal governor underneath that round cover. If it's leaking there it won't shut off.
    Miller xmt304, Miller S22 p12, Miier Maxstar SD, Miller 252 w 30A, Miller super32p12, Lincoln Ranger 9, Thermal Arc 181I with spoolgun, Hypertherm 10000 ,Smith torches. Esab 161lts miniarc.

  13. #13
    Join Date
    Dec 2018
    Posts
    1,963

    Re: Compressor Relief Valves?????



    I just had a bit of time yesterday to throw this together. Needed to air up a rear tire before going up to the hay meadow.

    Anyways...…………….I'm leaning towards either the motor bearing, or belts

    BUT THEN THE STUPID THING QUIT MAKING NOISE AFTER POPPING ALL THE VALVES

  14. #14
    Join Date
    Apr 2006
    Location
    Soda springs,Id
    Posts
    4,790

    Re: Compressor Relief Valves?????

    Maybe it was just crying and needed a little lovin'!!
    Mike
    Ol' Stonebreaker
    "Experience is the name everyone gives to their mistakes"
    Hobart G-213 portable
    Miller 175 mig
    Miller thunderbolt ac/dc stick
    Victor O/A setup
    Makita chop saw

  15. #15
    Join Date
    Mar 2009
    Location
    MN
    Posts
    5,160

    Re: Compressor Relief Valves?????

    Clean or replace the tank check valve. They can get gummy over time and not seal. This will allow leaking back through the head or pressure switch. Other symptoms can be hard starting and failure to reach shut down pressure. Symptoms can be intermittent.

    You say it hits 175, but won't shut down. Verify pressure switch is functioning correctly by backing it off a few turns to shut down at a lower pressure.
    My name's not Jim....

  16. #16
    Join Date
    Jan 2015
    Location
    Hamilton Ontario Canada
    Posts
    345

    Re: Compressor Relief Valves?????

    Boostinjdm Has it right, too high of pressure will make the belts squeal as the motor has to overcome the pressure in the compressure that it was not designed to do.
    Welders: IdealArc AC/DC 250
    Lincoln AC 225 converted to AC/DC
    O/A torches
    Lots of Hammers Clamps and Grinders

  17. #17
    Join Date
    Oct 2014
    Posts
    576

    Re: Compressor Relief Valves?????

    Quote Originally Posted by farmersammm View Post
    I just had a bit of time yesterday to throw this together. Needed to air up a rear tire before going up to the hay meadow.

    Anyways...…………….I'm leaning towards either the motor bearing, or belts

    BUT THEN THE STUPID THING QUIT MAKING NOISE AFTER POPPING ALL THE VALVES
    But is it shutting down normally and dependably now ? They don't usually just fix themselves. Lol.

    How was it running and not building pressure. That is a lot of air to be going nowhere. If it was turning pressure should have been rising if switch wasn't shutting down at 175. ????
    Last edited by danielplace; 04-23-2019 at 02:49 PM.

  18. #18
    Join Date
    Dec 2018
    Posts
    1,963

    Re: Compressor Relief Valves?????

    I think you guys were right about the belts.

    I haven't used the compressor till today.

    Turned the switch down to a lower cutout pressure like suggested, and let her run. Still wants to run up to 170 before shutting down.

    And...….the sound does come back when it's at 170, but pressure doesn't rise. Gotta be belts are slipping......she ain't turning enough to put pressure out maybe...still turning, but not making additional pressure.

    I dunno crap about these things.

  19. #19
    Join Date
    Apr 2011
    Location
    minnesota
    Posts
    1,959

    Re: Compressor Relief Valves?????

    Depending on how many hours you have on it the valves in the head could need to be rebuilt. Does it start normally or is it slow to go with pressure in the tank? If slow to start could be the tank check valve. If the tank check valve is leaking it will continue to leak out the unloader when not running
    Millermatic 252
    millermatic 175
    miller 300 Thunderbolt
    lincoln ranger 250
    smith torches
    lots of bfh's
    If it dont fit get a bigger hammer

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
RSS | Home | Penton Media | Contact Us | Subscribe | For Advertisers | Terms of Use | Privacy Statement