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  1. #1
    Join Date
    Nov 2008
    Location
    southeast U.S.A.
    Posts
    16

    RTAA EXV test failure

    Greetings,


    Having some trouble with a RTAA 80 ton. I replaced both EXVs and the EXV board. I started getting nusiance trips "EXV failure" on both circuits every now and then. But now, circuit 2 will not run at all. I can run the diognostic and the valve drives both ways. I understand that the EXV board sends out a pulse to test the windings before a startup. Has anybody else had simular faults?

    Thanks,
    eric

  2. #2
    Join Date
    Jan 2009
    Location
    Not in Iran
    Posts
    1,083
    If u changed that already and that has not fixed ,. New wiring, just saying ,
    no signature blast'em man blast'em
    !!!KILL THE TERRORIST!!!

  3. #3
    Join Date
    Dec 2009
    Location
    Southern US
    Posts
    504
    Didn't we ask this a few days ago! More info! Amps, pressures (verified). At start up and shut downs, trips! Entering and leaving water temps.
    Just more info!
    I'm good at making things cold...You can ask my first two wives!

  4. #4
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,310
    Double post?

  5. #5
    Join Date
    Aug 2006
    Location
    Columbus Ohio
    Posts
    1,980
    You need your pro status. Trane EXV's are covered in depth in the pro chiller section.
    UA LU189

    10mm, because it's better than .45acp

  6. #6
    Join Date
    Apr 2012
    Location
    Paper Street Soap Company
    Posts
    2,304
    So you had one go out and need to replace the board, both cables and both valves because they don't carry the old valves anymore.

    I'll be glad when these RTAA's are just a bad whiney thermistor eating memory.

    Is it possible the initial diagnoses was wrong and you're dealing with the same issue but with two new valves and a board ?

  7. #7
    Join Date
    Nov 2008
    Location
    southeast U.S.A.
    Posts
    16
    Another tech condemed the old EXVs. They were now obsolete, so when I replaced the EXVs, I also replaced the board (The EXV motor windings were completly different). I started receiving faults right off the bat. But after double checking the connections and running the valves through a diagnostic, they seemed to work OK. Then one the circuits, usually #2, would shut down on the EXV failure fault, but clear and restart. Now #2 will not pass the start up electical test no matter what I do. It really bothers me that the valve works perfectly but fails the little pulse test on startup.


    Thanks

  8. #8
    Join Date
    Apr 2012
    Location
    Paper Street Soap Company
    Posts
    2,304
    So the machine is inoperable ? Seems you still have an issue.

  9. #9
    Join Date
    Aug 2006
    Location
    Columbus Ohio
    Posts
    1,980
    You did run new EXV wiring right?
    UA LU189

    10mm, because it's better than .45acp

  10. #10
    Join Date
    Jan 2009
    Location
    Not in Iran
    Posts
    1,083

    Yo

    Bite the bullitt and call the big dogs in

    If u want my
    no signature blast'em man blast'em
    !!!KILL THE TERRORIST!!!

  11. #11
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    4,330
    Quote Originally Posted by zoofer View Post
    Greetings,


    Having some trouble with a RTAA 80 ton. I replaced both EXVs and the EXV board. I started getting nusiance trips "EXV failure" on both circuits every now and then. But now, circuit 2 will not run at all. I can run the diognostic and the valve drives both ways. I understand that the EXV board sends out a pulse to test the windings before a startup. Has anybody else had simular faults?

    Thanks,
    eric
    is this a remote barrel?
    "Mother" is the name for God on the lips and hearts of children....The Crow

  12. #12
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,310
    Did you run new wiring or change the plugs??? The pinout is different.

  13. #13
    Join Date
    Oct 2010
    Location
    GREECE
    Posts
    32
    Hi,
    Just an info I want to share about new EXVs.
    If you remove the EXV cable from module while in operation you have good chances to burn out module. Maybe your new module is defective!!
    Check according to PART-SVN118B-EN August 2009.
    CV

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