Results 1 to 7 of 7
  1. #1
    Controlswiz's Avatar
    Controlswiz Guest

    Scroll Compressors allergic to refrigerant liquid flood back - are they?



    Have come across frequent scroll compressor failures on Heat Pump Chillers. Are scroll compressors allergic to liquid flood back or is it something to do with the reverse valve surge while change over? Has someone experienced such a thing happening often?



  2. #2
    Join Date
    Feb 2007
    Location
    UK
    Posts
    2,479
    Rep Power
    45

    Re: Scroll Compressors allergic to refrigerant liquid flood back - are they?

    Generally scrolls are seen as more forgiving to liquid flood back than old fashioned rotarys.

    However, why is there liquid flood back in the first place? It's not good for any compressor.

    Also, surge when the reversing valve change over??? Surely the compressor is idle for this?


  3. #3
    Join Date
    Aug 2010
    Location
    Southeast Penna.
    Age
    31
    Posts
    27
    Rep Power
    0

    Re: Scroll Compressors allergic to refrigerant liquid flood back - are they?

    Don't know about chillers, but some split resi heat pumps don't kill the compressor for defrost. Suction pressure spikes briefly and the compressor sounds like it's taking liquid, makes me cringe every time.

  4. #4
    Join Date
    May 2006
    Location
    Australia
    Age
    48
    Posts
    12
    Rep Power
    0

    Re: Scroll Compressors allergic to refrigerant liquid flood back - are they?

    Hi
    Did you check for oil being washed out and compressor killed from lack of oil? Also scrolls hate operating in a vacuum and can lock up. Add more oil usually helps especially if the coil runs lower temps and gas velocity is low

  5. #5
    Join Date
    Mar 2009
    Location
    KZN, South Africa
    Age
    63
    Posts
    2,212
    Rep Power
    20

    Re: Scroll Compressors allergic to refrigerant liquid flood back - are they?

    Cut the old compressor up & look at the level of carbon deposits. If excessive, then likely failure due to oil breakdown at excessively-high compressor exit temperatures.

    This is a common occurrence for hot-water heat-pumps, for instance.

    What fluid is the condenser dumping heat to?
    Engineering Specialist - Cuprobraze, Nocolok, CD Technology
    Rarefied Technologies ( SE Asia )

  6. #6
    Join Date
    Oct 2001
    Location
    Nottingham UK
    Posts
    5,733
    Rep Power
    51

    Re: Scroll Compressors allergic to refrigerant liquid flood back - are they?

    Installing a suction accumulator would protect the compressor from liquid floodback. Sort of a basic requirement on a reverse cycle heat pump.

  7. #7
    moideen's Avatar
    moideen is offline Veteran Poster I am starting to push the Mods: of RE
    Join Date
    Apr 2008
    Location
    u.a.e
    Age
    48
    Posts
    417
    Rep Power
    22

    Re: Scroll Compressors allergic to refrigerant liquid flood back - are they?

    Better to replace the accumulator, because accumulator oil return orifice and screen may be plugged with trash or may become plugged shortly after a compressor failure. This will result in starvation of oil to the replacement compressor and a second failure. Ensure the crank case heater is working at off cycle. After replacement the compressor, rest of the oil to be cleaned through suction and liquid line filters. Use a 100% alumina suction filter drier and remove it after 72 hour operation. During the next start up, record the sump temperature to observe the system flood back.

Posting Permissions

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