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Wireless Thermostat C wire again.

I'm sure that someone has asked this already, but I really can't find it. I wan't to install a Honeywell Wireless Thermostat to our Gas Steam Boiler Burnham our current thermostat only uses the two wires (heat only) Red and W. The Wireless thermostat's need that C wire connect to them and I currently do not have a third wire.

The Honeywell Focus pro is the thermostat we are considering Honeywell YTH6320R100. The receiver gets mounted in the basement close to the boiler, etc, but I have no idea how to connect a C wire to it. I opened the front panel of the boiler, but there are a ton of wires in there. The only thing are saw was two blocks with wires connected to them that were labeled with numbers and not any letters. Can someone please help me with this? I know it;s not rocket science, but it has me completely confused I also asked an Electrician and he had no idea either.

Thank you in adavance.


  • Zman
    Zman Member Posts: 7,446

    For a t-stat to have constant power it needs to have a dedicated common. A 2 wire system has a hot, but since it is wired in series with a load, it does not have a common. You can get the common of the transformer that is powering the t stat.

    If you post a picture or drawing, you can get more specifics.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Bio
    Bio Member Posts: 278
    C wire

    I removed the jumper on the tstat, connected RW to the boiler and RC & C to a UL rated transformer to an electrical outlet, at least that's what honeywell recommneded and works beatiful
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