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Woodstove replacement - Will old stack/piping handle new stove?

Post in 'Classic Wood Stove Forums (prior to approx. 1993)' started by bigmike0601, Nov 10, 2012.

  1. bigmike0601

    bigmike0601 New Member

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    I bought the sierra to replace my older adobe style open stove. Now, my father in law says don't burn anything until I pay alot of money for someone to inspect it first. They can't see me for weeks...I need you help.

    The older (orange) stove had 8" pipe to ceiling. The newer sierra is 6" with couplings to 8" at ceiling as you see in pics. I looked up the pipe during replacement and it's 8" internal diameter all the way up (clean too). The attic pipe and roof stack looks to be 10" or even 12" pipe maybe. So, the attic all the way up to roof must be double walled correct? I burned 4 logs to get it real hot (no, father in law doesn't know nor can I tell him) and I felt the attic pipe and it's cool to touch. The single walled pipe is 23" from edge of pipe to wall behind the stove. I will put a heat safe rug in front of the stove.

    His main concern: The older stack was not meant to handle the sierra's much more intense heat output. The older stove was open and more decorative than anything else (according to him). Is he right? Will I burn the house down and kill his daughter and grandchild? If so, what can I do to prevent this? I not, what I can tell him to get him to relax?


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  2. Backwoods Savage

    Backwoods Savage Minister of Fire

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    Having a stove that calls for a 6" flue and then putting that into an 8" flue can cause some problems. The reason is that there is so much more space in the 8" that you actually lose drafting. Double wall should be good until going through the roof where it has to be class A. It does not appear this chimney is very high so with the reduced draft on the flue and a short chimney you may not be able to make it work. I'll let others chime in on this one and wish you good luck.
  3. Slow1

    Slow1 Minister of Fire

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    Designing a safe and effective chimney system takes a little bit more than just making the pieces fit diameter wise. I suspect that you already realize this but wanted to point it out as much for others reading it.

    Now, clearly I'm no expert on these things (there are some on the board and I hope they chime in) but from the pictures you posted that does not look to be class-A piping in the attic there and I suspect that the system you have likely would not be up to current building code in many areas. Code may not be necessary but safe is (in my book).

    If you want to make the FIL feel comfortable and know with the highest degree of certainty that the system is in fact safe, pay to have it inspected by a qualified expert. You never know what may have happened to the system between the top and bottom - i.e. are there any holes in it or anything? That looks to be a 'classic' system to put it mildly and I would want to be sure it is up to the job before really putting it to the test (i.e. letting my family sleep in the house with a fire burning).
  4. alfalfa

    alfalfa New Member

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    I'm no expert but I can tell you I used an increaser to go from 6" to 8" without any problems. Two things I did notice though...You will need a hearth extension infront of your stove, a rug will not meet code. Also from the position of the screw in the photograph of the single wall. It looks upside down. The crimped end of the single wall needs to point down towards the stove. I can't really tell from the photo...if I'm wrong, my apologies!
    PapaDave likes this.
  5. corey21

    corey21 Minister of Fire

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    I am no expert but the install looks unsafe.
  6. Hogwildz

    Hogwildz Minister of Fire

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    galvanized is no good. Get the proper Class A
  7. bigmike0601

    bigmike0601 New Member

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    The piping could only go together one way and the 90 came with the stove from previous owner so I'm pretty sure it isn't upside down. There are no leaks in the system. I will extend the hearth.
  8. bigmike0601

    bigmike0601 New Member

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    What can you tell is galvanized? Why is it unsafe?
  9. David Tackett

    David Tackett Member

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    Personally, I would replace everything. I would also make the chimney on the roof taller to get more draft. I am not an expert though, just an old school wood burner.
  10. Slow1

    Slow1 Minister of Fire

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    The way it is supposed to be is that each pipe is crimped into the next such that if anything were to drip (i.e. liquid creosote) inside the pipe it would flow into the next pipe toward the stove. IF connected 'backwards' then any drips would be much more likely to flow between the crimp and out of the piping system making a mess and potentially a hazardous situation for you.

    I don't know about how the previous person had it configured - but if it was in fact connected incorrectly I wouldn't want you to suffer any negative consequences as a result of old mistakes.
    PapaDave likes this.
  11. Hogwildz

    Hogwildz Minister of Fire

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    The photo showing the pipe as it goes through the ceiling, through the attic to the roof, is def galvanized. Unless it is some kind of s.s. double or triple wall Class A with a galv. outer shell. It is unsafe, can be toxic, and not up to temp standards. From what I can see in the photos, your stove pipe looks like it is run backwards. The male end should be running down into the female end.
    PapaDave likes this.
  12. bigmike0601

    bigmike0601 New Member

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    Thanks for all the responses. Looks like FIL is right again...I think I might as well replace the stove since im doing everything else anyway. A stove with flue exit on top to keep my existing pad. I need to research stoves now. I'll post a new thread for recommendations there.
  13. bigmike0601

    bigmike0601 New Member

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    I will be getting a new epa rated stove with flue 6" flue exit at top. Also, I will get new black single wall pipe to ceiling that is put together correctly. My question below:

    Is the galvanized pipe in attic really something to be concerned about? I will have 6" all the way to ceiling where it will transition to 8" internal diameter all the way up and out. The galvanized pipe in the attic is 12"OD. It's double or even triple walled pipe in there. Is there any real toxicity concern here? I'm more worried that it may not get hot enough for proper drafting...Comments?

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  14. Mrtwostick

    Mrtwostick New Member

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    the pipe should be fine as long as its CLASS A chimney and UL listed
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  15. corey21

    corey21 Minister of Fire

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    Galvanized pipe can not withstand heat like a class A system can.
  16. rwhite

    rwhite Minister of Fire

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    I would have that inspected. I've never heard of galvanized wood stove pipe.
  17. Sprinter

    Sprinter Minister of Fire

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    You will likely have to replace the chimney with a proper 6" stainless class A. It's a lot more difficult to get a chimney hot enough for a good draft with the newer stoves than it was with the old smoke dragons and 8" may be too large, not to mention whatever code might say about your existing system, and most manufacturers specify 6" all the way. Take a look at the installation manuals for some stoves that you might be interested in.

    Probably should have an experienced installer take a look.
  18. jeff_t

    jeff_t Minister of Fire

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    There is plenty of class A pipe out there that is SS inside and galvanized outside to keep cost down. It is often installed in a chase to protect it from the weather.

    However... you need to find out what you have. Is there label on it anywhere?
  19. HDRock

    HDRock Minister of Fire

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  20. Sprinter

    Sprinter Minister of Fire

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  21. begreen

    begreen Mooderator Staff Member

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    The galvanized outer jacket is not an issue if this is class A pipe. DuraTech can be purchase with a galvalume outer jacket still. However, that needs to be confirmed to be sure that this isn't triple-wall air cooled fireplace pipe. You want to know this for sure. If it looks like the pipe is air vented and without an inner insulated jacket, replace the pipe.

    Based on the other shot, I think there is a good chance that this chimney needs replacement. It looks like it was setup for the old freestanding fireplace then hacked to accommodate the old stove.
  22. begreen

    begreen Mooderator Staff Member

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    Going to merge threads to reduce redundant posts and confusion.
  23. bigmike0601

    bigmike0601 New Member

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    Is it crazy to run 6" class A system right up through my existing 8" pipe? This would be pretty easy in comparison to replacing everything. Anyone ever heard of someone doing this?
  24. Heatsource

    Heatsource Minister of Fire

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    ^ i'd just run insulated(wrapped) single wall satinless or dura liner up thru the old stack
  25. begreen

    begreen Mooderator Staff Member

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    I have some reservations about this suggestion. First, it looks like the pipe is going to need to be taller in order to get sufficient draft for an EPA stove. Second, is that legal to have as a connector? I wouldn't think so and I suspect neither would an insurance co or inspector. For peace of mind and an easier installation, especially if going to a double-wall connector for improving draft, I would to this by the book and remove the current setup completely, then install a proper class A flue system.

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