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Can traditional fireplace and woodburning stove share a flue?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by jc1426, Oct 2, 2006.

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  1. jc1426

    jc1426 New Member

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    I have a 1200 sq ft 1930's log cabin with a large traditional fireplace (brick chimney) positioned in the center of the cabin. On the back side of the fireplace, we have a very old potbelly stove that vents directly into the brick chimney. I'd like to replace this old stove with a new modern freestanding model and would like to vent it into the existing chimney. Unfortunatly, the stove and fireplace would share a single flue. Is this advisable? We have been operating the old stove and fireplace together without problems. We haven't had any problems with the draft. Is it possible to run a flue pipe for the new stove all the way up the inside of the chimney and still use the fireplace? The chimney is quite large. If that isn't a good idea, could we just continue to vent the new stove directly into the chimney. What problems would this create? For a number of reasons...(to many to list here)...it's not possible to run a new flue.

    Any advice would be greatly appreciated.

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  2. MountainStoveGuy

    MountainStoveGuy Minister of Fire

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    No, unfortunatly no solid burning appliance can share a flue with anything. they all need there own flue. You would have to stop using the fireplace and just use the stove.
  3. begreen

    begreen Mooderator Staff Member

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    If it's a really big flue can two liners and two stoves be run in the same fluepipe?
  4. MountainStoveGuy

    MountainStoveGuy Minister of Fire

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    Absolutly, but thats hard to accomplish when the fireplace would require so much volume. Now if there was a woodburning insert in there, then no problem whatsoever, but you need the room obviously.
  5. Rhone

    Rhone Minister of Fire

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    I was wondering the same thing as BG when I saw Marty's 13 x 13 flue, I was thinking he could easily fit a couple 6" liners, maybe even four uninsulated ones. If you look at his installation, that's one lonely 6" pipe in that flue.

    Hmm... imagine looking at Marty's chimney from the outside and seeing four liners popping out the flue. *:eek:)
  6. Shane

    Shane Minister of Fire

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    Technically the two liners is still against code. I'm quoting NFPA here (the unrecognized bastard code) but I'm sure there is similar language in IMC as well but they require a wythe of atleast 4" between the liners serving separate flues. IN our area our AHJ has told me that I can run a gas or pellet liner so long as I meet the required clearance to combustibles between the two liners.
  7. begreen

    begreen Mooderator Staff Member

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    That's my thought. Assuming there is room for a pair of 6" liners. Then I'd put a nice stove that has the firescreen option in the fireplace and update the potbelly.

    Edit, sounds like Shane has nixed this arrangement.
  8. MountainStoveGuy

    MountainStoveGuy Minister of Fire

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    well learned something new today, as usual. Had no idea that you needed 4" of space, most of the chimneys i have seen have a flue tile width seperating them.
  9. jc1426

    jc1426 New Member

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    Just curious. What is the reason that you can't have two solid burning appliances share a single flue? (i.e. fireplace and wood burning stove). Is it (A) safety issue or fire hazard, (B) concern that the stove won't heat as efficiently as designed or (C) concern that the gas/smoke won't vent and that you could get smoke back into the room, (D) other?
  10. MountainStoveGuy

    MountainStoveGuy Minister of Fire

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    because if one flue is large enough to handle two appliances, then neither one would draft properly if there not both being burned at the same time. You would also get smoke coming out of the lower appliance if they had common flues. And i shure there will be more added to that, but its one of the very basic rules of this industry.
  11. elkimmeg

    elkimmeg Guest

    Essentially code reads one flue one applaince A flue cannot be shared unless gas burner and gas hot water heater But never for solid burning appliances. The reason the flue is so large is the fireplace requirements whaat ever the fire place opening is the flue area =1/10 of it ususlly the fire place flue is sized for the opening now if you reduce the opening size the fireplace can no longer be used Also code prohibits the area around a line from being used. Be green posed and interesting point. what about two separate liners? Shane is correct that masonry flues have to be separated by a solid masonry wyth. Masonry flues have joint,, where flue lentght liners may not? This is a good question. Is it possible to have two full lenght liners in the same chase?
  12. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    And the four inch wythe requirement makes me look ruefully at the two 12 X 7 flues in my chimney that are 1/2 inch apart at the crown. Surely laid side by side all the way down.

    In fact I don't think I have ever seen a dual flue chimney with four inch seperation. Ever.
  13. elkimmeg

    elkimmeg Guest

    bb that code was introduced in 1998. Prior to that, two flues could share the same chase, providing the joints were no less than 7" separation.
  14. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Hmmm.. My guy only missed it by three inches.
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