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Thread: Nest 3 Gen and Honeywell W8835a1004 Board

  1. #1
    Junior Member

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    Nest 3 Gen and Honeywell W8835a1004 Board

    I was hoping to connect three new Nest 3 Gen thermostats to our existing forced warm air and central air cooling system. The HVAC system was installed in 2006 and works perfectly. The system has 3 zones with powered dampers. The control board has a 3 wire system to each of the 3 Honeywell programmable thermostats. My question is:
    1. Can I install the Nest thermostats with this board or do I need a newer generation board?
    a. If I can use the existing board, I already know that I need a C wire to power the Nest therms, however, the existing therm wires are labeled 1,2, and 3. They are not labeled as you might think they should be and the control board, where the therm wires connect, is also labeled correspondingly 1,2 and 3.
    b. If I can use the existing board, I am assuming that the therm wires 1,2 and 3 are used to call for heat, cooling and one is for power, but I do not know which is which.
    c. If you have any idea which is which, I would appreciate some in-site.
    3. If i need a new board, can someone recommend one that will work with the system I have and the Nest 3 gen thermostats.



    I would appreciate any helpful responses as I am having difficulty finding any solutions to this point. I have attached a photo of the board, schematic of the board and thermostat connection at the wall.
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  2. #2
    Senior Member

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    1 - Your system uses a proprietary 3 wire thermostat feed so Nest or any other regular thermostat won't work with it. 1, 2, 3 are ground, power, and data (or something like that).

    3 - Looks like you have a 2 heat / 2 cool system with 3 thermostats. An HZ322 Honeywell zone panel should work.

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