Woodburner Installation Question

Discussion in 'HVAC Heating & Cooling' started by 98ZJUSMC, Feb 19, 2012.

  1. 98ZJUSMC

    98ZJUSMC New Member

    Messages:
    25
    Location:
    Tunnel Hill, Ill
    I am trying to plan a Woodburner install as per the following diagram:

    Woodburner Detail 1.jpg

    The woodburner would stand within a cinder block enclosure leaving 12" of clearance to each side and 8 inches to the back. The front would inset approxiamately 8 inches inside the inner edge and the top of the woodburner would have 36" of clearance to the start of the frame above it. I plan to support the triple wall stack by lagging a support collar into cinder block just below the start of the wood framing transitioning to triple wall at that point. Going up the flue, I would set 9" of clearance from the triple wall to the combustible wall. I want to leave the flue box open to a point just above the upstairs vent to allow the unit to push heat into the upstairs living room, as noted. I want to veneer the entire enclosure with stone. I will use the units' blower to push heat into the downstairs rec room. Does anyone see any problems or obvious no-no's here?

    Thank you very much for your time and consideration.
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    I would check with the AHJ on that design. I think there needs to be proper fire separation between floors. The fact that you're going outside the envelope and then back in, clouds the requirement.

    It's not really clear what path it will take, but I think the convection airflow could reach temperatures that would require a class B vent that I think your chase won't qualify as.

    You mention triple-wall but not a brand. Most triple-wall I am familiar with uses air to cool. The air is usually drawn through a vented chase or attic but your chase appears to circulate indoor air so it might suck too much air out of the home.

    Why not go with a modern EPA approved factory made unit that has been UL or WH tested and has clear installation guidelines that the AHJ can easily interpret? Modern EPA stoves burn very efficiently. I installed a RSF Onyx in my home and heat it with around 3 to 4 cord a year. Mine has a 650 CFM central heat blower for the ground floor and I vented the chase into the room where it passes through the top floor. While it has a gravity B vent option that I could have used, I chose to go with the blower.
  3. 98ZJUSMC

    98ZJUSMC New Member

    Messages:
    25
    Location:
    Tunnel Hill, Ill
    Thanks for the tips! I would be installing a brand new free stander. The size of the enclosure would be determined by my choice (around 28-30 " wide). So, you're saying that because this would convect air from the basement, through the flue enclosure and then into the upstairs I may have safety issues? I was under the impression that flue pipe (double and triple) was basically air tight. All I am really trying to do is trap the rising heat and use it upstairs. I am trying to build in it like that due to space limitations in the Rec Room. Interesting. Thank you, Ligetfa.

    EDIT:

    OK. Wait a sec. By chase, do you mean the Chimney Cap? I would build the Chimney enclosure to run the triple wall stack up to 2' above the extended line of the roof peak, per minimum code. Brand of triple wall. I'm not sure. I removed the orignal woodburner some 12 years ago. The prior homeowner built a wood panelled 1 by wall about 4 inches from the back of the unit. I burnt two fires in it and then shut it down. That wall got hot!! In a subsequent remodel of the kitchen directly above, I had to remove the flue box and figured an outside wall was a better placement anyway. I saved the triple wall stored away in the attic.

    EDIT2:

    I checked out that RSF Onyx. Very, very nice. Could you give me a ballpark dollar figure for the purchase and install?

    Thanks again!
    Last edited: Feb 19, 2012
  4. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    OK, so now I'm really confused cuz it's nothing like the pic. Can you draw us a pic of what you have in mind?

    A chase is the vertical cavity that the chimney is running through.

    If the air exchanged between floors isn't so hot as to require a B vent, you could probably satisfy the AHJ using a floor grate with fusible damper.
  5. 98ZJUSMC

    98ZJUSMC New Member

    Messages:
    25
    Location:
    Tunnel Hill, Ill
    OK, so now I'm really confused

    Heh....Sorry. Yeah, I basically would just like to enclose a free standing woodburner into a cinder block alcove with 12 " of clearance around the unit. 36" above the top of the woodburner itself, I would wood frame the chase up to the Chimney cap. I wanted to block off the chase just above the upstairs vent to trap the rising warm air and waft it into the living room with the low volt fan. Then, continue the triple wall all the way up to the cap. The air should be no warmer than the air within 12 inches or so of the unit itself. I probably misused convection to describe the airflow. The chase would be completely outside of and attached to, the existing exterior wall and end up looking like a fireplace chimney. Sorry, I confuse myself all the time...:-D

    From the inside of the room, it would look essentially like this after I verneered the cinder block with stone or brick:

    chimneyliningsuffolkandnorfolk009001.jpg
    Last edited: Feb 19, 2012
  6. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    Make sure the stove you choose is approved for alcoves... many are not. Look over your triple-wall flue to determine if and how it is air cooled. You will still need to transition to it from the smoke pipe with some sort of ceiling support.
  7. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    I designed my home with wood heat in mind. I built my home in '98 and did my own install. I also retrofitted a RSF Onyx into my former home in '93 so I had a good idea of how the stove would perform in my current home. I don't recall what the costs were at the time.

    The second time around, I wanted to go with the taller Opal for the larger firebox but the wife didn't like the look of it with the double doors. They've since come out with the single door Opel 3 that would be my choice if I had my druthers. I don't care for the look of the new Onyx 2. The original Onyx looks like their current Oracle 2.
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