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  1. #1
    Join Date
    Sep 2009
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    Carrier Heat Pump with no 24 Volts at Contactor

    Carrier Heat Pump
    Serial# 4798E05500
    Model# 38YRA018310

    Model# FB4ANF024
    Serial# 4498A15145

    Diagnose: 2 Carrier Heat Pumps not running. Found no 24V at contactors on both units. Replaced both boards and contactors. 1 unit is now running and contactor pulls in correctly. 2 unit still doesn't have 24 volts at contactor. Switched boards to eliminate a new "bad" board. 1st unit started again with the board that was in the 2nd heat pump and is running correctly. I have 24V on my wire to the heat pump C, R and Y. C=Common, R=Power, Y=Compressor Contactor. I pulled the connector from the board and I'm still reading 24V on the above. So, I've eliminated the board and the connector. I do not have 24V coming out of the board to the contactor.
    What am I missing?? Low or High Pressure Switches not allowing the contactor to pull in?? Some help would greatly be appreciated!!!

  2. #2
    Join Date
    Nov 2006
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    Quote Originally Posted by harlee37 View Post
    What am I missing??
    The rules for posting here.

  3. #3
    Join Date
    Aug 2009
    Beatrice, NE
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    Read your wiring diagram and follow it to your problem. If you don't know how to do this ask your boss or go back to school. Sorry if I seem a bit rough but I get tired of parts changers that don't really know how test and diagnois a problem so they change parts till it is fixed, which makes the rest of us look bad.

  4. #4
    Join Date
    Jan 2004
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    Questions and discussions pertaining to HVAC for the home. No pricing, no DIY, please read, Please read site rules, Thank you.

    If your in the trade, get your post count up to 15 and apply for pro membership.
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    Thread closed.
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