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help with wiring wood boiler thermostat to run gas furnace forced air blower

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by rallen12, Dec 15, 2012.

  1. Downeast Farmer

    Downeast Farmer New Member

    Joined:
    Jan 20, 2013
    Messages:
    65
    It was the heat exchanger in the plenum, not the boiler. Jeez, and English is my native tongue....

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  2. Downeast Farmer

    Downeast Farmer New Member

    Joined:
    Jan 20, 2013
    Messages:
    65
    I'm a bit lost here and probably not asking this correctly because I don't really understand the discussion so far. I'd like to use my oil furnace with a heat exchanger from a biomass boiler. I'd like the normal function of the oil furnace to be preserved in case I can't tend to the biomass. I'd like a circulator to come on, get hot water into the heat exchanger, and only then for the blower fan to come on, both in response to a T-stat. Isn't this best? How do I do it? Put me out of my misery here....
  3. stee6043

    stee6043 Minister of Fire

    Joined:
    Aug 22, 2008
    Messages:
    2,272
    Loc:
    West Michigan
    This depends on how the user sets it up. Most OWB's run a single circ pump that runs 24/7 and the house thermostat only controls when the fan comes on in the furnace. Many of us indoor burners, especially those of us with storage, will have a circ that sends water into our tanks when the boiler is running at proper temp but we'll also have a second circ pump that sends water to our heat exchanger/load when needed.

    I personally control both the furnace fan and my second circ pump (for the heat exchanger) with a second thermostat and a relay. I only run water through the HX when there is a call for heat.
  4. Fred61

    Fred61 Minister of Fire

    Joined:
    Nov 26, 2008
    Messages:
    1,650
    Loc:
    Southeastern Vt.
    Run your circulator off the room thermostat and launch the furnace fan with a snap switch attached to the return line of the coil. That way you won't get a blast of cold air before the coil is up to temperature.

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