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    TomM10's Avatar
    TomM10 Posts: 3, Reputation: 1
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    #1

    Feb 2, 2009, 08:13 PM
    Honeywell RTH7400 Wiring
    I am replacing an old thermostat that had 6 wires. It had W,O,G,R,C,and Y. I reconnected all but the O. I can't find any help where this wire should go or if it should be connected at all.
    Please advise. Thanks!
    MarkwithaK's Avatar
    MarkwithaK Posts: 955, Reputation: 107
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    #2

    Feb 2, 2009, 08:26 PM

    What kind of system do you have? Heat pump? Gas?
    TomM10's Avatar
    TomM10 Posts: 3, Reputation: 1
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    #3

    Feb 2, 2009, 09:05 PM

    I have an electric heating with central air conditioning unit.
    Thanks!
    MarkwithaK's Avatar
    MarkwithaK Posts: 955, Reputation: 107
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    #4

    Feb 2, 2009, 09:06 PM

    Heat pump?
    TomM10's Avatar
    TomM10 Posts: 3, Reputation: 1
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    #5

    Feb 2, 2009, 09:15 PM
    No sir.
    dac122's Avatar
    dac122 Posts: 463, Reputation: 17
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    #6

    Feb 3, 2009, 06:17 AM

    Can you provide make/model of your air handler and outdoor unit; old thermostat model number and what color wire the O is and what terminal it was on that old stat.
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