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  1. #1

    Walk-in compressor short cycling

    I just recently set up a walk-in cooler and I am having a slight issue. I git the lines ran and it is charged up and all that fun stuff. I did have a bad solenoid so I replaced that. Now it is shutting off at temp, which it didn't do before, but now once it shuts off it kicks back on every 30 seconds or so but only runs for a second or two. It sounds like there is a hissing sound coming from the compressor. It almost sounds like there is pressure bleeding back into the line where it then kicks the compressor back on long enough for the pressure to pump down. My question is, is there something in the compressor, seals, o-rings or such, that could be causing this? Could it just need a rebuild or a new seal/gasket kit? Any help would be greatly appreciated.

  2. #2
    Join Date
    Jul 2000
    Location
    Guayaquil EC
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    10,478
    It sounds like a leaking discharge valve.

    Assuming this is a semihermetic, you can replace the valve plate assembly.

  3. #3
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,918
    Ditto.



    You have leaking discharge valves. I'd verify it with gauges, but the hissing sounds almost makes that unnecessary.

  4. #4
    Yes it is a semi-hermetic. So the valve plate assembly would cause it to bleed back? I can put my gauges on it if need be to find out. But there is definately a hissing sound coming from within the compressor best I can tell. Guess I will order me a new assembly.

  5. #5
    Join Date
    Jul 2000
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    Guayaquil EC
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    10,478
    Also, please fill out your profile and post a bit about your HVACR background.

    We just want to know who we're dealing with before we start handing out free advice.

    No DIY is a strict rule around here.

  6. #6
    Join Date
    Sep 2004
    Location
    oc
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    57
    [QUOTE=TheFireman89;2019743] I did have a bad solenoid so I replaced that. Now it is shutting off at temp, which it didn't do before, but now once it shuts off it kicks back on.




    Do you know what a pump down is???
    How and what did you charge it with???
    What was wrong with solenoid?
    How did you find the solenoid to be bad?

  7. #7
    Join Date
    Nov 2003
    Location
    Rochester, New York
    Posts
    392
    [QUOTE=ersham;2022205]
    Quote Originally Posted by TheFireman89 View Post
    I did have a bad solenoid so I replaced that. Now it is shutting off at temp, which it didn't do before, but now once it shuts off it kicks back on.




    Do you know what a pump down is???
    How and what did you charge it with???
    What was wrong with solenoid?
    How did you find the solenoid to be bad?
    Agree with this. That solinoid could be leaking by causing a rise in pressure and starting the compressor everfew seconds. Varify that solinoid isn't leaking by before you "rebuild" the compressor.

  8. #8
    The solenoid was doing exactly what you had described. I have already pumped it down and replaced it. I verified that it was indeed bad. With the old one still in it would keep getting colder (due to the freon still flowing past the solenoid). Now it is staying at temp like it should but short cycling fater than it was with the bad solenoid. I can hear a hissing coming from the compressor. I also talked to a couple of different people I know here locally and they agreed with the other guys that it is the valve plate. I have one ordered and I should have it today or tomorrow.

  9. #9
    Join Date
    Oct 2008
    Location
    Virginia
    Posts
    23
    Just be sure you didn't damage the new solenoid body (assuming it isn't flare style) by overheating while you were sweating it in. It almost sounds like pressure is getting past it while it is satified on temp. If overheated, the plunger inside the valve body may be damaged and not seating properly.

  10. #10
    Join Date
    Sep 2008
    Location
    Western PA
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    25,918
    Quote Originally Posted by jloshotz View Post
    Just be sure you didn't damage the new solenoid body (assuming it isn't flare style) by overheating while you were sweating it in. It almost sounds like pressure is getting past it while it is satified on temp. If overheated, the plunger inside the valve body may be damaged and not seating properly.

    This is where a good set of gauges pay for themselves.

    While the hissing points to the compressor, if the solenoid is nearby, that could throw the guesstimate diagnosis off. .

    A simple test would prove it and make you a hero, rather than a best guess and being a zero if you are wrong.

    Good luck.

  11. #11
    I already replaced the solenoid. That was the first problem I ran into before this one. The old one was leaking. I verified with gauges that it was not the new solenoid. I got my new valve plate assembly yesterday. I tore into it last night and all is good now. Works like a charm. The old reeds were wore out. You could feel the indentation in them from where they were seating over the ports. Finally fixed and ready to go. Thanks for all the input.

  12. #12
    Join Date
    Oct 2008
    Location
    Virginia
    Posts
    23
    Glad to hear you got it sorted out Fireman

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