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Thread: Reversing a compressor

  1. #1
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    Is there a way to try and reverse rotation of a mechanically locked single phase compressor.

    I ran into a situation where I made sure all starting componets were good along with triangulating compressor windings on a small semi-hermetic reach-in freezer compressor. I sure would of liked to be able to try and free up the thing temporarily to see if anything else had gone south or caused compressor problem in first place.

    Thank you for any replies!

  2. #2
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    Use an Annie.

  3. #3
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    I try to switch the start and run to see if you can free it up. I would just condemm it since it will most likely happen again.

  4. #4
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    Originally posted by Freezeking2000
    I try to switch the start and run to see if you can free it up. I would just condemm it since it will most likely happen again.
    I'd do that plus I would pull the head (carefully not tearing gasket ) and push down the pistons.

    If that won't move it you're done .

  5. #5
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    I have been known to kick the hell out em.
    Hey cockroach, don't bug me! ©

  6. #6
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    Originally posted by Diceman
    I have been known to kick the hell out em.
    (in truth, Dicee gives the job to Jack, and he kicks them)

  7. #7
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    reverse

    I didn't notice if this unit is hermetic or semi-hermetic,
    the sealed tin can, alittle hard to open up and take head off, I have had one recently lock up when trying to start by the oil pump end, are you sure the start parts are good,
    usually if new start parts won't work, unit is bad...
    or if you know how to wire in a test lead, if pressures are equalized, compressor should run..
    hem

  8. #8
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    Dice you have some merrit in kicking the hell out of it. I have seen guys hit them with a hammer to free up tin cans before.

  9. #9
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    Originally posted by Freezeking2000
    Dice you have some merrit in kicking the hell out of it. I have seen guys hit them with a hammer to free up tin cans before.
    I've got a three pounder that has been known to put a nasty divot into an AE4440.

    A true "Annie" can reverse it, but like previously stated, it'll only get you out of the woods, after that, at the end of that long dark tunnel, there will appear a light. It is the approaching train. get yourself a new compressor.

  10. #10
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    If I determine that the compressor is stuck I usually just condemn it and replace it. In the old days you could try the Annie deal and reverse the rotation to get it going and the customer would be truly grateful. Today if you do something "heroic" like that you will be married to it because the customer believes you actually fixed it the first time.

    Sure there are instances where you can free one up and it runs fine for years, but that's the exception not the rule. I'm in this business to make a profit and I don't like to have to go back and "re-fix" something for free.

    I've got a K-Body Copeland on a C-Store ice cream freezer unit that I whacked with my 3 lb hammer on a Sunday morning a few years ago, it started and I haven't had a problem since..............go figure.

  11. #11
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    Please!

    An HVAC/R professional does not whack a compressor...

    He performs an "impact adjustment."

  12. #12
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    I had a Meat prep room go down on a Sunday about 2 years ago .
    A Copeland 5 or 7 hp (I forget)was locked . The setup was all singles and had been remodeled and retrofitted so many times , it would have been a real deal change it. Anyhoo, I was desperate. It had a 1965 serial# so I had nothing to lose.
    I reversed and reversed and reversed and reversed and reversed and it finally broke free. When it did I cried like a little girl (tears of joy). It ran for about a year and a half until the store got new Hussmann racks.

    I swear I used to salute that compresser everytime I passed it after that day.

  13. #13
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    Originally posted by emerson climate tech
    Please!

    An HVAC/R professional does not whack a compressor...

    He performs an "impact adjustment."
    I like that. I usually describe it as "fine tuning" the system.

    Again, since we're in this for profit, how much should I charge for using the "Impact Adjuster"?

  14. #14
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    Thread Starter
    Thanks to all for the info!


  15. #15
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    Originally posted by icemeister
    Originally posted by emerson climate tech
    Please!

    An HVAC/R professional does not whack a compressor...

    He performs an "impact adjustment."
    I like that. I usually describe it as "fine tuning" the system.

    Again, since we're in this for profit, how much should I charge for using the "Impact Adjuster"?
    By the whack!!! ("Impact Adjustment")

  16. #16
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    May 2004
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    The capacitor in the starting winding causes a hesitation in the ac sine wave, effectively making the motor a two phase motor which gives it direction of rotation because the magnetic fields build up in the windings at different times. So, moving the capacitor to the run winding changes the direction; that is also why 3 phase doesn't need a start winding.

  17. #17
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    "Impact Adjustment"

    REMBER:

    TO Fix does not allways mean repair,

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