CoAire Heat Pump - No outdoor fan
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  1. #1
    Join Date
    Mar 2006
    Location
    DFW
    Posts
    3,967

    CoAire Heat Pump - No outdoor fan

    Im trying to fix a heat pump. I may work on 1 or 2 a year so they are definitely my weakness. Anyway, its a CoAire model number COTH-48M2Z. I replaced the defrost control board after I found I have 24 volts input but did not have 24 volts output at the board. The low pressure and high pressure switches were both closed.

    With the new board installed the contactor now closes and the compressor comes on, but the fan does not. There is 120 volts going into the board at CN20 but no voltage coming out on the FAN terminal. If I bypass the board the fan comes on. Why is the 120 volts not leaving the new board? Thanks.

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  2. #2
    Join Date
    Sep 2002
    Location
    Virginia
    Posts
    3,039
    sounds like the defrost sensor is lying , and telling the board its time for defrost

    is the suction line getting hot when this occurs ?

  3. #3
    Join Date
    Feb 2011
    Location
    Georgia
    Posts
    185
    Kick it over in ac mode and see what happens

  4. #4
    Join Date
    Mar 2006
    Location
    DFW
    Posts
    3,967
    Could someone please give me the PDF file with the wiring schematic in this heat pump. I'm going to use your suggestions but wanted the schematic before I go back. Thanks

  5. #5
    Join Date
    Dec 2001
    Location
    St Louis, MO
    Posts
    164

  6. #6
    Join Date
    Feb 2013
    Location
    Florida
    Posts
    69
    Some boards you have to disconnect control voltage to momentarily and then go into a manual defrost to "learn" what a clean coil is

  7. #7
    Join Date
    Mar 2006
    Location
    DFW
    Posts
    3,967
    Thanks everyone. Tremendous help !!!
    Eat a slice of Humble Pie.

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