Compressor lugging while filling...diagnosis?
Close
Login to Your Account
Results 1 to 12 of 12
  1. #1
    Join Date
    Jun 2002
    Country
    CANADA
    State/Province
    British Columbia
    Posts
    2,597
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2065

    Default Compressor lugging while filling...diagnosis?

    Good morning All:
    I have a Gardner Denver 2 stage reciprocating compressor vintage 2001 that's recently started acting up.
    When I drain it completely and then fill it, it starts lugging badly and the belts squeal at around 60 PSi, then it returns to normal and fills the rest of the way to 160.
    Sometimes it does it sometimes not.
    It's got 5 ponies and the flywheel speed is getting down to within maybe a couple of hundred RPM.
    It's got a 2.5:1 reduction ratio and the nameplate motor speed is 1725

    I took the belts off, degreased them and the pulleys, dressed the belts with belt dressing spray, retensioned them and fired it up again.
    It's not much better.
    The crankcase has oil (recently replaced), I drain the water daily, the compressor turns over with what feels like acceptable compression with free movement at bottom dead center and no evil noises during a manual stroke, the motor spins freely...all seems to be good in that department.
    So I don't think it's the crankcase bearings or the motor bearings.

    Short of taking the whole thing apart to try to find a problem, any ideas what might be happening.
    A stuck delivery valve to the high pressure side maybe?

    Are the valves typically accessible from the outside of a recip or do I have to tear the whole goddamn thing apart?
    I've never had a 2 stage recip compressor apart...where do I start?

    I assume I have to get a gasket kit first before I start undoing bolts.
    Do these things have piston rings like a car?
    Do the cylinders typically get a hone before the whole works goes back together?

    If this is going to be a major undertaking, I'll probably have it serviced by the seller rather than farting about with it myself.
    So my question is mostly about what kind of effort this is likely going to be.

    Cheers

    Marcus
    Implant Mechanix • Design & Innovation > HOME
    Vancouver Wire EDM -- Wire EDM Machining

  2. #2
    Join Date
    Mar 2006
    Location
    Winnipeg,Manitoba
    Posts
    120
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    28

    Default

    The place to start will be the check valve. That will be between the line going into the tank, and the tank itself. Usually located just outside the tank. There are multiple styles of checks, so a piccy would nail it down. Penetrating oil and a calm disposition go a long way.

  3. Likes Limy Sami, Bobw liked this post
  4. #3
    Join Date
    Feb 2011
    Location
    BFE Nevada/San Marcos Tx
    Posts
    1,232
    Post Thanks / Like
    Likes (Given)
    1103
    Likes (Received)
    668

    Default

    If it has reed valves you would have to pull head to clean or replace them, if it has disk valves, they can be cleaned or replaced without pulling the head. Yes the pistons have rings just like a car engine, but I don't think you need to worry about that, yet. Check your check valve first, and get some pics.

  5. Likes Limy Sami liked this post
  6. #4
    Join Date
    Jan 2007
    Location
    Norfolk, UK
    Posts
    18,930
    Post Thanks / Like
    Likes (Given)
    14437
    Likes (Received)
    14500

    Default

    ''When I drain it completely and then fill it, it starts lugging badly and the belts squeal at around 60 PSi, then it returns to normal and fills the rest of the way to 160.
    Sometimes it does it sometimes not.''

    I'm in the check valve camp, sounds like it could be sticking and / or some sort of blockage that needs 60+ psi to open it.

    Another thought - is there any type of rubber hose between the pump and receiver (sorry - tank)

  7. Likes Bobw liked this post
  8. #5
    Join Date
    Jul 2011
    Location
    Americus, Georgia
    Posts
    406
    Post Thanks / Like
    Likes (Given)
    531
    Likes (Received)
    123

    Default

    Check valve is about the only component to fail and give intermittent blockage. The gauge you are reading must be between the check valve and tank. A gauge between the compressor discharge and check valve would show high pressure when the lugging occurs. Remember that pressure is resistance to flow.

  9. #6
    Join Date
    Dec 2012
    Country
    AUSTRALIA
    Posts
    2,269
    Post Thanks / Like
    Likes (Given)
    10
    Likes (Received)
    688

    Default

    Pretty typical symptoms of belts slipping.....belts slip until they get hot and sticky,then grip and off she goes......so first replace the belts,even if they look OK,and tension them properly......while doing that ,try the belt in the small(motor) pulley section.....if the new belt fits down in the vee to the bottom,then the pulley will need replacing.......Ive seen quite new pulleys worn out,.....Chinese made rubbish ,even on a domestic machine.

  10. #7
    Join Date
    Sep 2014
    Country
    UNITED STATES
    State/Province
    Georgia
    Posts
    349
    Post Thanks / Like
    Likes (Given)
    259
    Likes (Received)
    128

    Default

    If you have a clamp-on amp meter see if it is drawing too many amps in the trouble zone. It is probably a valve problem that is keeping the high pressure cylinder from doing its part of the work.

  11. #8
    Join Date
    Mar 2006
    Location
    Auburn CA
    Posts
    435
    Post Thanks / Like
    Likes (Given)
    5
    Likes (Received)
    39

    Default

    I second putting a current meter on it. I also agree if it is lugging down the check valve is a good place to look.

    But if it is slowing down as much as you say there should be smoke coming out of the motor. At way less slow down than you have stated the motor would be drawing nearly locked rotar current. This should trip your over current protection in a short amount of time (perhaps a few seconds). The ammeter will provide instant clarity to this issue.

    My first thought was also slipping belt as that is the only way I could envision that much of a slow down with out tripping the over current device. But the RPM change at 60 PSI suggests a different root cause than a slipping belt.

    First step remove the line from the output of the compressor. If it spins free the problem is down stream.

    Bill

  12. Likes Limy Sami liked this post
  13. #9
    Join Date
    Jul 2012
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    2,932
    Post Thanks / Like
    Likes (Given)
    1136
    Likes (Received)
    1185

    Default

    When I first fired up my HD 4hp 2 stage compressor something was clearly wrong. I found out the rubber plug was never removed from the exhaust port before assembly and ended up at the check valve plugging it up. The compressor didn't bog down much at all and it's just a cheapie.

  14. #10
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    15,557
    Post Thanks / Like

    Default

    Trouble with the valves between the stages ?

  15. #11
    Join Date
    Jun 2002
    Country
    CANADA
    State/Province
    British Columbia
    Posts
    2,597
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2065

    Default

    Gentlemen, thank you all for your insights.
    I pulled the check valve, brushed the accumulated crap off it it and tossed it into the ultrasonic cleaner.
    All seems to be good again.
    We will keep fingers crossed and pray to the Compressor Gods, but it's run for a full day now and she's chuggin' away with no bogging down and no squealing.

    Cheers

    Marcus
    Implant Mechanix • Design & Innovation > HOME
    Vancouver Wire EDM -- Wire EDM Machining

  16. Likes Gordon Heaton, paul39, Bobw, Limy Sami liked this post
  17. #12
    Join Date
    Jan 2007
    Location
    Norfolk, UK
    Posts
    18,930
    Post Thanks / Like
    Likes (Given)
    14437
    Likes (Received)
    14500

    Default

    Quote Originally Posted by implmex View Post
    Gentlemen, thank you all for your insights.
    I pulled the check valve, brushed the accumulated crap off it it and tossed it into the ultrasonic cleaner.
    All seems to be good again.
    We will keep fingers crossed and pray to the Compressor Gods, but it's run for a full day now and she's chuggin' away with no bogging down and no squealing.

    Cheers

    Marcus
    Implant Mechanix • Design & Innovation > HOME
    Vancouver Wire EDM -- Wire EDM Machining
    Having an ultrasonic cleaner's cheating Marcus

    Well done mate


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •