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  1. #1
    Join Date
    Jul 2007
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    Lennox GCS11 blower runs all the time

    Working on older Lennox RTU where the blower runs all the time when it should not, unit controlled by 20vdc stat. Struggled with this unit for a while today, came down to finding a cmc2 blower delay timer motor that does turn. I dont have any real experience with these rtus(dc to ac using logic panel) Is this cmc2 a part still found? and I was wondering if not, what could I do to control the blower. Also anouther RTU same model, jumps out but stat does not seem to work(20v dc stat, where you slide the temp desired like a light dimmer with no fan control) Are these style stat available are is there a way to use a so called conventional stat?

  2. #2
    Join Date
    Jul 2007
    Delta BC Canada
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    The fan control is not run throught the Honeywell w 973 panel. It is a seperate 24 volt circuit.

    If it has a switching subbase the contacts will be # 9-10 on the subbase it will be connected to C 9&10 on the low voltage terminal block.
    If it is just a transmitter (themostat without switching subbase) .Locate the k-23 relay that is used to switch the indoor fan motor.

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