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  1. #1
    Join Date
    Feb 2011
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    CGAC Chiller control diagnostic

    Hello and thanks for reading this post!
    I was called to a CGAC unit that shows the following:
    Compressor 2 is running and loading and unloading, compressor 1 is off with all 3 LED's off (LEDs on the honeywell control) Safety check ok.
    Why would compressor 1 not try to start?

    Second problem: There is another of these units close by that will not run at all.
    When power is applied, the control starts flashing the LED second from the top (compressor 1) this is also the start mode LED. Safetys check good on this machine as well.

    Thanks for any help!

  2. #2
    Join Date
    Aug 2006
    Mixing oil and fire with a big spoon.
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    welcome! a couple of things first...

    1. this a very technical as detailed as possible
    2. always provide the FULL model number and if possible, the serial number
    3. learn how to use punctuation...some guys here are pretty particular...and good so you want to be on their side
    4. we convert all pressure drops into pressure drops of pudding...learn to convert

    as for the first chiller...
    it is possible that the chiller loaded up the Number 2 compressor first and has not needed to start the Number 1 does perform Lead/Lag functions.

    as for the second chiller...
    i am not familiar with a 'flashing' #2 LED. a solid #2 LED means that it is in the start mode. if it stays in the start mode, the module may have failed.
    Don't step on my favorite part of the Constitution just to point out your favorite part.

    Political Correctness is forced on you because you have forgotten decency.

  3. #3
    Join Date
    Dec 2003
    45th Parallel
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    If I remember correctly, the flashing #2 LED means that your Chilled water setpoint is lower than the LTC(low temp cutout).

    Try raising the setpoint and see if it goes away.

    These controls are getting a little hazy in my mind, haven't worked on them for so long, but I think the LTC may be set by a resistor????
    “If your work speaks for itself, don't interrupt.” ~Henry J. Kaiser

  4. #4
    Join Date
    Feb 2011
    Post Likes
    Thread Starter
    Thanks for the replies.
    The flashing #2 LED went away with a power cycle.. go figure. Compressor came up and ran.

    Got the other unit to run with a reset also, it came out on low temp leaving compressor which does not make any sense as only one compressor shut down and both are run by the same control with only one temperature probe.

    Thanks again for the help

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