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  1. #1
    Join Date
    Jan 2005
    Posts
    48
    This will prolly keep me up thinking about this all so might as well share it with you all....avid reader and first post. Im a tech with around five yrs exp and still a noob and learn and read this forum pretty much everday, anyway to the problem.

    Went on a return call today from our PM tech, he had a a/c with low pressure @ 200/40. Calls me up and tells me he tried to charge and no pressure change and then ran out of freon. No idea how much he put in either, he has no scale.

    so go there today and find this
    compressor at 13.8A
    ambient 80
    liquid is 220psi and 80 degrees
    vapor 34psi and 49 degrees

    s/c 28
    s/h 38

    temp drop on coil is 72 in 64 out 8 degree delta and cap. tubes are icing, a-coil otherwise is basically warm and dry.

    This is a Rheem 4T 12 seer condensor with a 3.5T ICP coil with TXV, coil was existing and we ran lineset ( I think) and set condensor and only 8 months ago. Anyway I know thats not every thing...airflow is good, lineset not kinked, coils clean and low humidity.

    So what Im thinking is a stuck almost closed TXV or god-forbid a plugged coil, also has a filter dryer but I think blockage is in the coil.

    Any ideas before I yank the coil/TXV on Monday....anything Im over looking? All help greatly wanted and highly appreciated!




  2. #2
    Join Date
    May 2000
    Location
    BENTON, KY 42025
    Posts
    339
    I ran into almost the same thing today. Heil 12 seer split heat pump running 205/32 with icing at the TXV. Warmed the bulb in hot water, switched to heat a few times and no change. Changing the TXV tomorrow.

  3. #3
    Join Date
    Jun 2001
    Posts
    3,916
    Sounds like a TXV bulb lost it's charge. Change it. Make sure the bulb or txv body doesn't overheat when brazing.

  4. #4
    What position is the bulb in?It never be at the bottom of the line,because the oil traveling with the refri.could act as an insulator and the bulb may not sense the refri.temp.leaving the coil.Put it at10 o clock or 2 o clock position.make sure you don't have a restriction at your new connections.

  5. #5
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,759
    Pull the sensing bulb and put it in warm water and see it it feeds more refrigerant.

    Sounds like trash got to the txv, or the bulb lost its charge.

    Disable the blower, and see if all the distributors are frosting the same.(they're distributor lines, not cap tubes)

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    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Jan 2005
    Posts
    48
    Thank you all for the replies, yes the bulbs at 10:00 but the h/o needed to leave so I didnt get a chance to test the bulb. I did tap the txv to see if it was stuck, figured might get lucky. Question for beenthere: what exactly will that tell me to watch the distribution lines for icing....am I understanding correctly that if 1 ices faster there may be a blockage there?

  7. #7
    Join Date
    Oct 2003
    Location
    west chester pa
    Posts
    343
    the blockage is the txv resticting flow of refrigerant into the coil which will freeze the distributer lines. sounds like a bad txv. when you replace it put the nex filter drier right b-4 the new valvealso.

  8. #8
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    You're right if one ices and the rest dont its restricted. but I'd pull that txv and check it before thinking the coil's blocked. Most trash should get caught in the txv's screen or their old as dirt(like mine) and have no screen then the trash will just screw up the txv itself.
    If everything was always done "by the book"....the book would never change.

  9. #9
    Join Date
    Jun 2005
    Location
    New York
    Posts
    207
    As beenthere said, its a Txv (or in let stariner is clogged). Most Txv failures are powerheads or inlet stariners. Just replace Txv at this point.

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