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  1. #14
    Join Date
    Nov 2011
    Location
    Charleston, Wv.
    Posts
    1,269
    Quote Originally Posted by jpsmith1cm View Post
    What damage would running without refrigerant cause?
    overheating, causing winding insulation breakdown.

  2. #15
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    24,947
    Quote Originally Posted by 71CHOPS View Post
    overheating, causing winding insulation breakdown.
    What do we have thermally protected motors for?

    They'll take a LOT more abuse than most people think that they will and keep running.

  3. #16
    Join Date
    Feb 2009
    Location
    Tallahassee, FL
    Posts
    5,821
    Quote Originally Posted by jpsmith1cm View Post
    What do we have thermally protected motors for?

    They'll take a LOT more abuse than most people think that they will and keep running.
    Not a Trane Scroll! Cooked Well Done for sure!

  4. #17
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    24,947
    Quote Originally Posted by SBKold View Post
    Not a Trane Scroll! Cooked Well Done for sure!
    Not familiar with the particulars of Trane.

    I wouldn't condemn one just because it ran without refrigerant for a while.

  5. #18
    Join Date
    Feb 2009
    Location
    Tallahassee, FL
    Posts
    5,821
    In my experience - the worst burnouts are scrolls.

    They really hate running with no refrigerant.

    They must approach thermal breakdown oil temp.

    Not saying everyone that runs for awhile is shot though. They just cant take much of it.

  6. #19
    Join Date
    Nov 2011
    Location
    Charleston, Wv.
    Posts
    1,269
    motor insulation temp. for most hermetic compressors is class H, or 356 degrees F, for an acceptable thermal life expectancy. Temps. higher than that, the varnish and insulation begin to break down pretty fast.

    it may function just fine for another few months or few years, after running without refrigerant cooling for an extended period of time.......just depends on how much you like to gamble i guess. i would want to know the factory megaohm rating compared to what it is after the loss of refrigerant, then decide from there on wether or not to condemn one.

  7. #20
    Quote Originally Posted by coilcleaner View Post
    How long has it been running flat? I would be concerned with where and how big the leak is before worrying about amp draw. Compressor probably has already been damaged.
    Yup, the leak was from one of the veins off the distributor rubbing up against the reversing valve. And i dont know how long the system was running flat. Im the helper, the tech talked to the home owner while i was outside.

  8. #21
    I appreciate everyones post thus far its helpful and a good learning tool!

  9. #22
    Join Date
    Jul 2009
    Location
    Columbia, MD
    Posts
    3,384
    ohming the compressor will tell you about insulation of windings. we cant tell how wore out the scrolls are and what not from possibly running with no lubrication.

    i would def do a good evacuation and put some quality driers on the system.

  10. #23
    Join Date
    May 2010
    Location
    Oxford, UK
    Posts
    336
    I wonder if running with no refrigerant would lead to poor oil return and bearings running tight and so a high running current. Depends how long its been running like that for.

  11. #24
    Join Date
    Jan 2012
    Location
    PAC-NOR
    Posts
    46
    Running a scroll compressor under 50PSI(410A) 20PSI(R22) with no refrigerant can cause arching, and winding degradation, at least according to Alliance. Its on most of their WCR forums and docs, mostly to keep techs from jamming the contactor in and pumping it to the ID without a recovery machine. YMMV

  12. #25
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,512
    When i find a system empty on refrigerant and i suspect damage in the compressor i give the home owner the option of replacing the compressor especially if the compressor is under warranty

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