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  1. #1
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    Carrier RTU Issues

    Good morning - I am trying to figure out what is going on with this Carrier RTU m/n 50PG-C28-CL50-AG, s/n 3406G40024. This unit has 3 scroll compressor circuit A has 2 in tandem and circuit B has 1 compressor. This unit uses Carrier's famous " scrolling marque" interface that is not working that well. I still have my navigator hand held. I have worked on many chillers using these controls, but circuit 2 comes up with a failure code I have never seen before "T-144" circuit B failure to pressurize. This is an R-410a system and is operating with 390# condensing pressure and 137# evaporator pressure. This was through system transducers than verified with actual service gauges. What am I looking at with this fault ? I have the correct pressure in the circuit. Any help would be appreciated. - GEO
    Once in a while everything falls into place and I am able to move forward, most of the time it just falls all over the place and I can't go anywhere-GEO

  2. #2
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    Mar 2008
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    Seen that on a mcquay it happened the CB tripped and the lead lag sequence selected that compressor to start. The other compressors then started and took over but it still had that fault. Not sure if it would do that on a carrier or not.
    Honeywell you can buy better but you cant pay more

    I told my wife when i die to sell my fishing stuff for what its worth not what i told her i paid for it

  3. #3
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    Quote Originally Posted by ga1279 View Post
    Good morning - I am trying to figure out what is going on with this Carrier RTU m/n 50PG-C28-CL50-AG Any help would be appreciated. - GEO
    Check your email.
    Instead of learning the tricks of the trade, learn the trade.

  4. #4
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    Thread Starter
    rundawg-- Thank you sir, very helpful indeed. I very much appreciate your comeback. -GEO

  5. #5
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    Quote Originally Posted by ga1279 View Post
    rundawg-- Thank you sir, very helpful indeed. I very much appreciate your comeback. -GEO
    Instead of learning the tricks of the trade, learn the trade.

  6. #6
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    May 2014
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    And the rest of us will never know . . . Guess I could look it up in the ComfortLink manual . . .
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

  7. #7
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    Quote Originally Posted by BBeerme View Post
    And the rest of us will never know . . . Guess I could look it up in the ComfortLink manual . . .
    I just emailed him the install and troubleshooting manual in hopes it would guide him to a conclusion.

    Because this is an "OPEN forum, I didn't post the manual here to the site.

    I'm also hoping he will return with his ultimate findings.
    Instead of learning the tricks of the trade, learn the trade.

  8. #8
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    What version ComfortLink does that unit have? The earliest manual I have is for the 6.x, and the error code T-144 doesn't even exist by that time.


    Quote Originally Posted by rundawg View Post
    I just emailed him the install and troubleshooting manual in hopes it would guide him to a conclusion.

    Because this is an "OPEN forum, I didn't post the manual here to the site.

    I'm also hoping he will return with his ultimate findings.
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

  9. #9
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    Quote Originally Posted by BBeerme View Post
    What version ComfortLink does that unit have? The earliest manual I have is for the 6.x, and the error code T-144 doesn't even exist by that time.

    The one I sent him is Version 4.x.
    Instead of learning the tricks of the trade, learn the trade.

  10. #10
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    Apr 2007
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    uk
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    The alarm is in version 5. Suspect it's a case of the compressor not starting after a command to start. No pressure differential seen between Suction and Discharge pressure.
    Gibbo

  11. #11
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    From the ComfortLink 4.x manual:


    Alert Codes T143, T144 -- Circuit Failure to Pressurize
    Alert codes T143, T144, and T145 are for circuits A, B, and C,
    respectively. These alerts have “Service Test” text that will be
    displayed if the alert occurred during service test. These alerts
    occur when the compressor turns on and the suction pressure does
    not drop at least 10 PSIG and stay there for the first 20 seconds
    AND the condensing temperature does not rise at least 5*F and
    stay there for the first 65 seconds (both conditions have to occur).
    These alerts cause a strike for the respective circuit. The alert resets
    automatically. The cause of the alert is usually compressor wiring
    causing reverse rotation or a faulty compressor.
    If you were a real tech, you'd solder a relay on that board and call it good to go.

    I do a triple evac with nitro to remove non condensables.

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