Tempwood with flue problems

PostNBeamSandwich Posted By PostNBeamSandwich, Dec 1, 2017 at 9:32 AM

  1. PostNBeamSandwich

    PostNBeamSandwich
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    Dec 1, 2017
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    Cape Cod, MA
    We have an unknown vintage Tempwood which came with our 1400 sq ft house when we bought it a year ago. We are wood heat only (4-4.5 cords of hardwood per year). The Tempwood is on a 6" stove pipe in a central chimney where its clay flue liner has collapsed into shards at the bottom, meaning the pipe can't ever be removed or replaced without disassembling the entire chimney from inside the house (way too expensive, not an option).

    Our mason, who is currently rebuilding the top of the chimney to stop water leakage, told us that the creosote build up in the stove pipe was extreme for one year of use (it gets professionally cleaned once a year). His opinion is that the 6" pipe is too small for a proper draft on the Tempwood, and thus we are getting dangerous creosote build up with our heavy use. He thinks we should put the wood stove into our fireplace flue (12" square clay flue, totally intact), or into a basement flue (7.5" square clay flue, totally intact). He thinks a wood stove wouldn't need a pipe inside either of the other two clay flues, and would produce less creosote.

    I've been reading on here for a while, but am a total newbie to wood stoves. From my reading, a 6" pipe is standard for modern catalytic stoves, but is it sized right for an '80s Tempwood? Would putting the Tempwood (or another, bigger stove) onto a 12" fireplace flue or a 7.5" basement flue help the creosote build up, or increase it due to slower drafting?

    My thoughts prior to the mason's suggestion was that our creosote build up could be because we have to smolder (shut down the vents) the stove over night and during the work day so that we still have embers when we wake/return and can restart the stove quickly, so we've only been full vents-open burning for about 5 hours in the evening and 1 hour in the morning most days. I had been thinking that a bigger stove would allow us to keep the air vents open over night and during the work day without having the stove go totally cold, maybe a mid Moe or Mama Bear or something similar. But, now knowing that we can't change the stove pipe, and that the flue liner is a mess, I'm kind of at a loss---help a newbie out? :)
     

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  2. begreen

    begreen
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    Nov 18, 2005
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    I thought the Tempwood flue size is 6". @pen do you know?

    The mason is trying to help out but the problem lies elsewhere I think. If this is a fairly recent development the likely culprit is the wood is poorly seasoned.

    I am concerned about running the stove on a defective chimney. That could be unsafe, but running without a stainless steel liner up the 12" flue would much less safe and would generate even more creosote if it drafted well at all.
     
  3. bholler

    bholler
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    Jan 14, 2014
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    Call a sweep chances are the chimney it is in can be fixed. And generally going larger will increase buildup not the otherway. Your flue should match the outlet on the stove which i think is 6"
     
  4. PostNBeamSandwich

    PostNBeamSandwich
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    Dec 1, 2017
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    Our sweep never said anything was wrong. He has cleaned the chimney since it was first built 30 years ago by prior owners, and never indicated there was a problem to them or us even though we told him we were having leaking through the roof. But during that same period (some time after it was built), the clay flue liner collapsed, the chimney crown disintegrated, and the top four courses of brick were totally lose of the mortar (you could pick them up by hand). So we don't know if we should trust his reaction, considering the mason's shock at how bad of a condition the overall chimney is in. We've only had the house, and the problem, for a year.
     
  5. PostNBeamSandwich

    PostNBeamSandwich
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    Dec 1, 2017
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    Thanks, we measured the pipe opening on the stove, and it is also 6". So the mason seems to be confused about that and the advisability of going bigger.

    We don't know how much of a problem this was before the last year, because we only bought the house last summer, and the chimney sweep who has always done the house since it was built never mentioned other problems (like a cracked, leaking chimney and collapsed flue) either.
     
  6. begreen

    begreen
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    The current chimney sounds like it may be unsafe. We can't say at a distance over the internet how bad the chimney is, but if tiles are cracked and collapsing then it needs a repair or at least an insulated stainless steel liner to make it proper for wood burning. The same liner is required for the larger fireplace chimney. Unfortunately it also sounds like you might also want to consult a new sweep, preferably one that is csia certified.
    www.csia.org

    Did you buy your firewood? If so, there is a good chance that it is poorly seasoned. This is not uncommon with wood sellers. Poorly seasoned wood can generate creosote rapidly.
     
  7. bholler

    bholler
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    Jan 14, 2014
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    Find a new sweep them
     
  8. PostNBeamSandwich

    PostNBeamSandwich
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    Dec 1, 2017
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    The owner of the business our prior sweep works for is the first guy listed as csia certified for our area.... Not really sure what to make of that!

    We did, from someone recommended by our local wood stove store as a reputable dealer of dry wood. We also acquired some of our wood from a friend, which had been dried in a barn for several years so it was dry as a bone. We don't know who the prior owner was buying wood from, so that could have been green, but the chimney was cleaned between the prior owner and our use.

    Is there any way the steel pipe could have been incompletely cleaned, so that the prior owner's green wood creosote build up was still there after our first cleaning? (this might be a super dumb question, sorry!)
     
  9. begreen

    begreen
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    Not a dumb question, anything is possible including doing a rush job that isn't thorough.
     
  10. fbelec

    fbelec
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    Nov 23, 2005
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    you also said you turn the air down to keep the stove going for restarts. what temp are you running on top of the stove. even dry wood would make a mess of that chimney if burnt too low. just to give you more info about what was said to you about a larger chimney i run a stove that uses 8 inch pipe into a clay lined 8.5 x 12 inch flue and run my stove hot and still make a mess of the chimney. so going big is not a good idea. if your wood is good and dry you need to run the stove hotter
     
  11. zig

    zig
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    Oct 10, 2014
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    I wouldn't mess with the chimney that needs repair like you describe. Use the 12x12 with an insulated liner installed. Don't just do a slammer install because the big flue size will make more creosote than you have now, dry wood or not. Wherever the brickwork is exposed to the cold outside air will cool the flue faster than the hottest fires can warm it up. I wouldn't trust any chimney you have without a liner based on the the one your dealing with now.
     

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