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ducting wood furnace hot into LP cold air return

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by huntingbuck101, Apr 8, 2008.

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  1. huntingbuck101

    huntingbuck101 New Member

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    Can you duct you hot wood furnace air into your LP furnace cold air intake as long as you make it so the fan on LP runs when the wood furnace runs?

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  2. brooktrout

    brooktrout New Member

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    Sure. But by the time the air goes through the ductwork, the plenum and out the supply registers, it will be cold again.
  3. huntingbuck101

    huntingbuck101 New Member

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    my furnace would be next to the Lp furnace, but on the main floor in a furnace room and LP is in the basement so the bottom of the wood furnace would be at the top of the LP to two separate rooms so it would be a short run between them.

    I was thinking the hot air from the wood furnace wood be to hot for the LP cold air intake because of possible electronics being cooled by the return air.

    My Dad has done this with a pellet furnace but he left about a 1' gap between the forced hot air duct on the pellet furnace and the LP cold intake. it's also in between a floor joist so it kind like the bottom of the duct is open. His air is around 85 and it does feel a bit cold out of the vents but it still heat the house very well. his furnace is around 75000 BTU max and mine wood be 135000 so I would think it would be better.

    what would you suggest I do?
  4. brooktrout

    brooktrout New Member

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    What do you mean by possible electronics being cooled?
  5. huntingbuck101

    huntingbuck101 New Member

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    I was told but a heat guy, that changing the air filter on a LP furnace doesn't only help keep the air clean it also keeps dust from getting on the electronics that are cooled by the return air.

    What would be in the inside? I don't know. It looks like it's all in the outside front. maybe a temp sensor.
  6. begreen

    begreen Mooderator Staff Member

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    What make and model "wood furnace" does this refer to? Is this a pellet stove?
  7. huntingbuck101

    huntingbuck101 New Member

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    the wood furnace is a Clayton 1600 and Pellet stove part is about some one else.
  8. Mike Wilson

    Mike Wilson New Member

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    This concept has been debated here ad infinitum. I recommend checking the convenient "Search" feature located in the top left hand side of your screen.

    It doesn't work well. I've tried it, others have tried it, and the voice of experience is that it doesn't work. Perhaps if you have a large basement mounted indoor furnace with a custom plenum, you might get some heat out, but your loss rate will be huge.

    -- Mike
  9. begreen

    begreen Mooderator Staff Member

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    I'm going to move this thread over to the boiler room for more assistance. This is a very basic unit, the manual is pretty weak and a crappy pdf file with overwrites of critical information. I also don't like that it takes room air for supply into the ductwork. This should be enclosed and part of the return air system. Seems like a negative pressure nightmare. I also disagree with the primary diagram for ducting and would have at least 6" ductwork plenum clearance from combustibles where this heater enters the ducting system.

    As far as tying it into the existing system, it is designed to be installed next to the furnace. I don't understand why on earth it would be installed on the floor above it. That is just wrong.
  10. muleman51

    muleman51 Member

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    I heated my house that way for 10 years. It worked quite well, all I had was a Papa Bear Fisher stove and an open cold air return above it. It kept the house very nice, I just ran my furnace blower all the time. The only part we didn't like was the mess and smoke puffs when filling in the house. It is really very simple.
  11. begreen

    begreen Mooderator Staff Member

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    And probably a code violation. The return air intake is required to be at least 10' away from the stove. Regardless, this is not a freestanding stove, it's a furnace.
  12. huntingbuck101

    huntingbuck101 New Member

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    I have a 12x26 ground floor room betwwen the house and the grage that I would like to use as a furnace room. It would keep the mess out of the house, and could store wood and it's gound level so no halling wood through the house and down to the basement.
  13. JustWood

    JustWood Minister of Fire

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    Why not just run HOT into HOT. I have a tri-level and it works fine. Stove being on the lowest level which is about 5' below highest level. No basement.
  14. sleepie

    sleepie New Member

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    i have read many posts on what can work and more on what does not work---if you give it the time and thought ---YOU WILL MAKE IT WORK--i know this because i did it with hot water and a section of baseboard in a room too far away from the stove,,it took some time and safety concerns--but along the way ALL WAS FIGURED OUT,,so all i can say is keep it up,,look read and be safe--but i'm sure it can be done with much experimentation---this is what makes America---have a great day----pat
  15. huntingbuck101

    huntingbuck101 New Member

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    I can get to the cold duct much easier
  16. JustWood

    JustWood Minister of Fire

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    They make insulated flexible duct that is very easy to work with. It runs around $1/ft. If you do run it into your cold maybe you could bypass the LP furnace just before you get to it . If you do have to run through the furnace I would definetly add an extra pre filter so your furnace doesn't become a dust/fire trap.
  17. begreen

    begreen Mooderator Staff Member

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    If this is the case then I would treat it as an independent heating system as per the manual instructions. However, be sure to provide return air from the heated space to the furnace or it will be sucking cold air in from the garage.
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