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    casey napton's Avatar
    casey napton Posts: 1, Reputation: 1
    New Member

    Aug 3, 2008, 10:51 PM
    Thermostat RTH230B not shutting off with ac on 2 wire
    Thermostat RTH230B not shutting off with ac on 2 wire thermostat RTH230B but have cold air&FAN IS RUNNING
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert

    Aug 4, 2008, 05:38 AM
    You need 3 wires to run ac on that thermostat correctly. One hot leg to RC one to green for the fan and one yellow for the a/c control. Some in the past have tried to combine the yellow and green under one lug or wire but that does not work with a digital thermostat.

    It can be wired for 2 wire a/c use only BUT you cannot use the green/blower connection at all so your blower has to be controlled by another means like a relay.

    SEE here.

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