Swap Flues?

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MANIAC

New Member
Hearth Supporter
Apr 17, 2007
89
Bridgton Maine
How much draft difference will I see by swapping the flues servicing my woodstove and furnace? My current setup is the furnace flue is thimbled in the basement into I believe an 8x8 clay flue. My woodstove is thimbled on the first floor into I believe and 8x14. With what seems to be a small amount of masonry work I could swap the flues servicing each unit. Does that make sense?

From all my lurking/learning around this forum I believe that I am at the very top of the spec as far as flue size for my woodstove and am likely not getting the best draft for the stove. I am new to burning so a draft issue is probably not going to be as obvious to me as it may be to some of you. The current setup works well and heats my home extremely well but I thinking with the change I may be even more efficient.

Just for some back round this is a brand new house and chimney. The chimney is interior as you can see and runs from the basement though the first and second floors and extends from the roof about 5 feet. The chimney run from the stove thimble to the top of the chimney I would guess to be around 20 to 25 feet.

Any thoughts?

Eric
 

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Given an interior flue, as it seems you have, my guess is that it will not make a major difference. Most rect flues are considered 8x13 OD, which makes them less than 7 by about 10.5 in my experience. Some are as small as 6" x 10".

I would leave it as is if things seem to work well.....BTW, very nice looking setup!
 
I was just thinking that I was on the top end of the 3X rule and figured I would ask.

Thanks for positive feedback on the setup. We love it but it's always nice to hear what others think of it.

Happy Holidays!!
 
Hi, I was running my old stove which I had for 26 years into an 8 x 12 clay flue and it worked fine. When I got my new stove about 7 weeks ago, I tried the same setup and the draft was lazy. Two weeks ago I installed a 20' rigid ss liner and now the draft is real active. I would say that the closer you can get to the recomended flue size for your stove the better.

Jim
 
If you had a problem, then the swap would help it. The symptoms of a lazy draft would be some smoke entering the house when you topload and it would be hard to get your secondary burn going; and then keeping it going. If you aren't having a problem, then why change. If you find you are having a problem, then it might be a better long term solution to go with a rigid SS liner to the exact spec, within your 8X12.
I am personally with the prior post, I had a Defiant CAT stove on my 8X12 and it worked perfectly, I changed to a Defiant NC and now the 8X12 does not have enough pull to function correctly with the refractory secondary burn mechanism. If yours does, go with it.
 
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