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  1. #1
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    Compressor floodback and burn out



    Over many years I have seen many hermetic and semi hermetic compressors that have had refrigerant floodback problems and then burn out after a relatively short time. Usually within the next 2 months. Although this does not happen to every compressor it happens to quite a few(Sorry I cant specify numbers). I have some of my own theories, I would be interested if any others had: A: experienced this and B: Had there own theory as to why this occurs. Or C: I am just deluded.
    I have experienced this on R22,R134a and R404a.



  2. #2
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    Re: Compressor floodback and burn out

    Hi Oldesky,

    Seems to be a common problem in Oz. I'm in Cairns (great place for business in A/C - it gets so damn hot here..) and I've been to plenty of jobs where the compressor has died within a month or two of replacement.

    I found the issues was usually 1 of 3 things.

    1. The TX was faulty (suoerheat was too low or too high)

    2. Condenser fan was in the process of failing (would run for an hour or two then seize)

    3. The compressor contactor was faulty (usually on 3 phase units, it might have high resistance on one phase of the contacts)

    Any of these is guaranteed to take the compressor out in a short period of time. I learned early on in the piece that when I do a compressor change, also change the contactor - no ifs or buts, check the condenser fan and do a superheat set up on the valve when commissioning.

    In this day and age where the lowest price wins, I'm finding that these are not the way of most others. It costs more in the short term in time and equipment to do this and so the margins are tighter. But I don't have warranty issues with the compressor supplier either and I don't have to go back to the job.

  3. #3
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    Re: Compressor floodback and burn out

    Scramjetman, I was really refereing to compressors that burn out that have had flood back problems but everything else in the systems appears OK. The floodback situation has been corrected and the compressor has failed somtime later. It has then been removed and inspected and apart from slightly more wear, the compressor is mechanically sound but burnt out.

  4. #4
    Join Date
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    Re: Compressor floodback and burn out

    Are you talking about rebuilds or brand new ones?

  5. #5
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    Re: Compressor floodback and burn out

    With flood back the damage is done when oil is diluted and bearing damage occurs. The extra low temps in sump will tweak the metal and compound the bearing wear with reduced lubrication. Add probable valve damage that regenerates hot gas to suction, then overheats compressor, as well flood back will flush any junk in the system into the sump.
    May take a week or month to happen. But will generally happen in hotter climates,sooner than later.

  6. #6
    Vlernar's Avatar
    Vlernar Guest

    Re: Compressor floodback and burn out

    it happen quite often in singapore , split unit type R22 gas.

    compressor temp raise daily and in 2 week or so , it just burn out the compressor due to overheated .

    any suggestion to cut down on this ?

  7. #7
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    Re: Compressor floodback and burn out

    Keep the return suction temperature down and this will keep your discharge temperature within operating limits.This can be achieved by correcting charge and superheat.

  8. #8
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    Re: Compressor floodback and burn out

    New compressors Scramjet.

  9. #9
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    Re: Compressor floodback and burn out

    Thanks for your contribution Magoo

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