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Blower motor distance from HX coil?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by MNBobcat, Jan 2, 2012.

  1. MNBobcat

    MNBobcat Member

    Joined:
    Sep 6, 2009
    Messages:
    120
    Loc:
    Minnesota
    Hi Guys,

    I have a 3-core, 22" x 25" water-to-air heat exchanger coil which I'm using to build a heater for a pole building.

    The case I made is large enough that I can mount the squirrel cage blower inside of the case with a filter on the back to filter in-coming air. However, this would result in the blower being about 5 inches away from the coil. Mounted that close, I'm concerned that only the center of the coil might be used.

    Just wondering how critical the distance is between the heat exchanger coil and the blower motor for best efficiency?

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  2. dogwood

    dogwood Minister of Fire

    Joined:
    Mar 22, 2009
    Messages:
    634
    Loc:
    Western VA
    Just an idea, but I bet you could fabricate, or buy, and place some kind of baffle in that 5 inch space that would direct the air to where you want it to go. A return air register cover might work if the opening on the squirrel cage's opening is big enough. You'd have to bend the baffles. How big is the opening on the squirrel cage blower?
  3. woodsmaster

    woodsmaster Minister of Fire

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    Jan 25, 2010
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    2,425
    Loc:
    N.W. Ohio
    I'm also thinking of building one of these. I'm going to buy a cheap box fan for it. Should be plenty of air movement. If you blow to much air threw it may feal like cool air.
  4. MNBobcat

    MNBobcat Member

    Joined:
    Sep 6, 2009
    Messages:
    120
    Loc:
    Minnesota
    Box fan won't work. They are made for free-air and will burn up under a load.
  5. Duetech

    Duetech Minister of Fire

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    Sep 15, 2008
    Messages:
    1,436
    Loc:
    S/W MI
    The blower on my oil furnace is probably 3 1/2 to 4 feet away from the W/AX in the plenum. To get the flow you desire baffles as dogwood suggested or louvre's to direct the air for wider coverage would probably be a good idea. There is going to be a lot of turbulence in there but I think you are right that it will be concentrated.

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