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Oval to round elbow?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by dkw45, Oct 6, 2010.

  1. dkw45

    dkw45 Member

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    Oct 6, 2010
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    SW MO
    I've got an old Wesco cook stove that I am wanting to install. The height of the 7" oval outlet on the stove is only 6 inches less than the bottom edge of the 8" thimble on my flue. I've seen several oval to round adapters but I can't afford to add any extra height. Has anyone dealt with an issue like this? Any ideas would be greatly appreciated.

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  2. tinknocker

    tinknocker New Member

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    Sep 26, 2010
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    Berlin twp., Michigan
    I'm not exactly sure what you have there but it sounds like you have a 7" horiz. opening in the back of your stove and a 8" flue runnning vertical and you need some kind of elbow to go from 7-8" round, I also assume that its single wall pipe.
    my first thought be to put a 8" to 7" reducing cap in the 8" opening and then a regular 7" 90 deg adj elbow than you should be able to oval one end to go over the oval on the stove. If your not familiar with a reducing cap its differant then a reducer because it doesn't add any length. its bascially a 8" round end cap with a 7" collar cut in it. You could also build a sheet metal box with a 8" collar in one side and a 7" collar in the other side, wouldn't look as nice but...........
  3. dkw45

    dkw45 Member

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    Oct 6, 2010
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    tinknocker, thanks for the advice. The stove has the 7" oval which exits vertically. The flue thimble is horizontal. I attached pics below. Basically, I need to come off of the 7" oval on the stove and then immediately elbow towards the thimble. I can't add much if any height to what the elbow already adds, so an oval to round adapter is out of the question. You mentioned using a standard 7" elbow and "ovaling" it to fit on the stove. If that would work, it would solve my problem. I didn't think it would have enough give to do that without separating the joints. Unfortunately, no one around here carries 7" inch pipe or I would pick one up and try it. I hate to have to order one and pay shipping just to find out it won't work. I may just have to bite the bullet and order one anyway.

    I guess if all else fails, I can install a new thimble higher in the chimney.

    Attached Files:

  4. SteveKG

    SteveKG Minister of Fire

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    Yes, that height restriction is the real problem. I used to have a cookstove with that same sort of flu outlet, oval-shaped. However, my stovepipe was going straight up to the ceiling and I was able to mash some stovepipe into shape. Could you get an elbow, 7 inch, shape one end to the oval, then a reducer or adaptor 7 to 8 inch..... As you mentioned, mashing it might cause openings in the elbow that would have to be carefully sealed. Not the best answer but perhaps it would work. The connection to the chimney opening will be no problem once you locate an appropriate reducer or reducing cap.

    Perhaps an expert will chime in. Perhaps you will ultimately have to have a one-off piece made at a sheet-metal shop. If you do that, you don't want them to use galvanized. I had to have a piece made for that aforementioned stove of mine, at a welding shop. It was not stovepipe, but the guy became interested in the project [something out of the ordinary for him and not boring] and he took it as a personal challenge to figure out how to do it. This will cost a bit, but if you have it made from good material, it should last your lifetime, and if it doesn't, you'll have the old one for a template.

    If you are willing and able to tap into the chimney higher up, which would of course entail a little brick work and some other hassles, that would solve the stovepipe part of the problem. It might just be worth it. You can easily cap off the current opening if you don't want to brick it in. Then you could use straight stovepipe to attach to the oval flu outlet.

    Let us know what you come up with. This is interesting. You don't need double-walled pipe with that brick behind the stove, so that helps a bunch.
  5. tinknocker

    tinknocker New Member

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    DK I see what you have there, you should be able to make this work.
    If you have 6" from the stove opening to the bottom of the 8" thimble you should have plenty of room.
    As far as ovaling that 7" elbow on to the stove it should work. In 40 years of doing HVAC work we never used oval pipe to hook up furnaces that had oval connectors on the flue we always just ovaled the pipe/elbows.
    also that 7" elbow is only going to have about a 3" throat radius on it so it will just use up 3" of your 6" space you have, so you could actually oval a short piece of 7" pipe on to the stove first and then connect your elbow to that.
    then get a 8"-7" reducing cap or just a 8" cap and 7" collar to cut into the cap, you could also cut the collar into the cap off center, near the top of the 8" opening which would give you another inch of height.
    if you can find a sheetmetal shop and buy from them there's not more then $10 worth of stuff there, they might not have black pipe but you could buy galvanized pipe and see if you can make it work.............just paint it black, its cheap to replace.
  6. dkw45

    dkw45 Member

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    OK guys, I appreciate the help. I'm in the process of building the hearth now. Once that is done, I'll move the stove in place and see what I can make work. I'll update with my solution in case it could help someone else.
  7. vvvv

    vvvv New Member

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    measure both the oval & the round with a cloth measuring tape. if they match, use a solid elbow [non adjustable]....no seams should allow for ovalizing....good luck
  8. dkw45

    dkw45 Member

    Joined:
    Oct 6, 2010
    Messages:
    8
    Loc:
    SW MO
    Thanks for the input. I had the same thought. Unfortunately, I haven't been able to locate a 7" fixed elbow anywhere. 6" and 8" are everywhere. Apparently, 7" is the black sheep of the stove pipe family.
  9. Shoot me an email at theheatelement@gmail.com I only post my address to members in need and normally at cost just to help out... I can get you that elbow for no problem at all..

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