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  1. #14
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,548
    TXV was wide open at the time this picture was taken.

    All heating vents were already checked and aimed away from this case. (Yes, it is an open air single-deck type case)

    Not to be a jerk, mccool, but how would low airflow contribute to this problem?


    Ok. Time for another hint. It hasn't worked right in a very long time if it ever worked right. Our company didn't install it, but we got saddled with the repairs.

  2. #15
    Join Date
    Feb 2006
    Location
    Phoenix,AZ
    Posts
    2,874
    What kind of defrost. If electric. Are the heaters on during cool?

  3. #16
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,548

  4. #17
    Join Date
    Feb 2006
    Location
    Phoenix,AZ
    Posts
    2,874
    Ok my last guess.
    Is the compressor correct for the application?

  5. #18
    Join Date
    Apr 2010
    Location
    San Diego, CA
    Posts
    202
    Compressor inefficient?

  6. #19
    Join Date
    Sep 2010
    Location
    Madison WI
    Posts
    77
    If the air curtain is ok and this is on a low temp rack Is it the longest run ? How is the case nexted to it ? I had two bunkers side by side and one would take ref from the case that would not maintain temp the case that was working was the problem I think I got gray hair from that job.

  7. #20
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,548
    There is an *assumption* being made and it is the SAME one that my tech made, that I made and that the other tech that I called for advise made.

    As I said, the factory guy got it in about 5 seconds. Made me feel about 3 feet tall.

    I actually think that a residential AC guy would have nailed it a lot faster than I did. From what I've read, those guys see problems like this more often than I do.


  8. #21
    Join Date
    Feb 2006
    Location
    Phoenix,AZ
    Posts
    2,874
    Did you assume it was a 404 system and it's actually something else? Or wrong TXV?

  9. #22
    Join Date
    Sep 2010
    Location
    Madison WI
    Posts
    77
    would like to know what that tech from the factory found I was born short . I just rebuilt an M1 Garand and they are not blue but gray.

  10. #23
    Join Date
    Oct 2009
    Location
    WI
    Posts
    114
    HP too low?

  11. #24
    Join Date
    Sep 2006
    Location
    Chicago
    Posts
    474
    Your guages are setup for 404a...I don't know what type of system you're working on but 185 psi head with 40* subcooling on a 404a machine seems weird. Seems more in line with 22. You could have the wrong txv capacity or nozzle. Or wong txv powerhead for refrigerant.

  12. #25
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,548
    Head pressure is adequate for system design.

    It is a mechanically subcooled system which accounts for the abnormal amount of subcooling.

    Refrigerant is correct as R404a. It is a rack system which will tend to operate on somewhat lower head pressure than conventional units or AC units.

    Rest assured, I WILL reveal the answer before the day is through, I just want to give any and all a shot at guessing.

  13. #26
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,315
    Were the readings shown in your pic taken back at the rack?

    I'm going to guess the liquid pressure at the entrance to the TEV was way below 183 psig...possibly as low a 90-100 psig...and still show a full SG due to the high subcooling.

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