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Major condensation problems. Quick question.

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by rbelden, Feb 5, 2009.

  1. rbelden

    rbelden New Member

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    I have a brick chimney lined with 8" liner that is approximately 25' total distance from thimble to cap. I am having problems with condensation pouring out of the thimble. It is definitely related to outdoor temperature & the temp of the stove. I have yet to find the exact point at which it occurs but I know that when the stove is less than full output it usually happens especially if it's colder outside. (<25 degrees) My question is if it would be a problem to drill 1" hole to the bottom of the liner and route that condensation to a dry well filled with gravel? I am a builder and have the tools for this kind of fix but I'm not sure if this is the best idea or someone might have a better fix. As you can see this is working wonders for the decorative stone I laid behind the stove. The house is only 3 years old and I had the liner cleaned 3 weeks ago. He said it looked great. By the way, the stove is a Vermont Defiant. Any advice is appreciated.

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  2. rumme

    rumme New Member

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    do you have a cleanout at the bottom of your metal chimney ?

    if not, it looks to me that the cresosote condensation is actually building up in your chimney..several inchs or feet and then escaping the only place it can...at your connection..

    I have the same problem with massive condensation, but I have a spring loaded trap door at the bottom of my steel chimney, that allows me to let all that gook out so it doesnt build up to where my stovepipe meets my chimney connection.
  3. rbelden

    rbelden New Member

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    Actually I don't have a cleanout on this chimney. The thimble is in my basement and below grade so there really was no way to install an exterior access point. I also didn't think this type of install (wood stove only) would require one since I have my liner cleaned yearly by my chimney sub. Apparently I was VERY wrong.
  4. snowtime

    snowtime Minister of Fire

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    A couple of thoughts. Is your 8" liner pipe and insulation or is it just a stainless liner. If just stainless than insulating the pipe will go a long way towards limiting the creosote. I think the hole at the bottom of the pipe is a bad idea. It will possibly let water out but it for sure will bring in air to make your chimney even more of a creosote machine.
    What was in this chimney before you installed the pipe? This could be creosote left over because the chimney was not cleaned properly before installation. The new pipe is heating the old chimney and you have a condensation problem. Perhaps you could look down the old chimney and see if there is any creosote?
    You should also check the top plate to be sure no water is getting in. Sometimes a good looking plate will not be sealed well.
    Well there are some ideas good luck.
  5. rbelden

    rbelden New Member

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    The liner is not SS. It's tile lined. This is a brand new chimney by the way (3yo). Thanks.
  6. DAKSY

    DAKSY Patriot Guard Rider Staff Member

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    Loc:
    Averill Park, NY, on Burden Lake II...
    Not sure from the pic if you have a clay thimble running into your chimney.
    If you do & you have a masonry adapter inside that, you need to run the masonry
    adapter father into the chimney...
    If you can get the adapter pipe AT LEAST 1" min into the terra cotta flue tile,
    the creosote will run down INSIDE the flue instead of inside the house...
  7. struggle

    struggle Minister of Fire

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    I had the exact same problems you have and the only fix was to reline the chimney with a 5.5" flex liner. Condensation is occurring because your tiles have shifted or cracked. No matter what I did I could not stop the leaking like you show until a liner was installed. Since the liner has been in place I have not had a hint of moisture from the chimney.

    Your condition is the perfect storm for a chimney fire as I had one after mine kept doing what yours is. I went to the trouble to seal my pipe into the tile liner really good to where the liquid would run into the stove and not onto the wall and shortly after the chimney fire took place.
  8. rbelden

    rbelden New Member

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    It is a tile thimble to tile liner application. That stove pipe actually runs through the thimble 16" or more (12" CMU block & chimney block surrounding flue tile). I have non-flammable insulation filling the small void between the stove pipe & thimble walls to prevent air bypass.
  9. struggle

    struggle Minister of Fire

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    Exactly as same as mine was. Pipe was at least 12'+ into the thimble. Now it is a flex liner all the way to the stove. I suspect something bad went wrong with a tile somewhere just as it did with ours.
    [​IMG]
  10. rumme

    rumme New Member

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    are you saying that the condensation is improving the chances of a chimney fire ? I ask because I have a condensation problem, but mine drains out the cleanout I installed at the bottom, when I open it each morning....so the condnesation never builds up high enough to reach the point where my inside stovepipe that goes thru my wall , meets the chimney ....the condensation gathers below that point....which seems to have the unexpected positive consequence of washing down any larger creostoe flakes from the sides of my chimney, to the bottom of my cleanout in the chimney
  11. struggle

    struggle Minister of Fire

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    Its my understanding that with a clay tile liner set up as I have that the tiles can shift and while you are burning wood the hot exhaust of the stove goes up the chimney and hits the cold air coming in where the tiles may have shifted or cracked and when this happens it does it continuously and the exchange between the cold and hot create a liquid creosote mixture that in my case started a chimney fire.

    I have no clean out like the OP has. So if you have an air leak into a clean out with a tile lined chimney I would think you will want to seal that up air tight. Your situation is a bit different it seems. DO you have a clay liner?

    After I installed the liner all of our leaking chimney problems went away since this gave us an air tight exhaust for the stove eliminating cold infiltration into the system.

    My chimney run is 24' long from top to the wall.
  12. ansehnlich1

    ansehnlich1 Minister of Fire

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    You said you're burning a Vermont Castings Defiant?

    Is it a catalytic model?

    Also, what type of wood are you burning? Is it dry?

    Do you have a moisture meter? If so, split a piece or two of your wood and let us know the moisture percent.

    One more thing, do you have a stove top thermometer? A flue gas thermometer? Any idea of the termperatures you are burning at?

    Could be as simple as wet wood, green wood, a bad catalytic converter in a catalytic Defiant (which I owned and operated one 2 years ago)

    Could be burning way too cool.

    Could be sucking cold air into the chimney from an unkown source.

    How about a pic of the stove :)

    And maybe a pic of the chimney outside?
  13. struggle

    struggle Minister of Fire

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    If of any use to OP my stove prior to the reline was a Vermont Castings Vigilant and when this problem started with the advice of people on here I completely rebuilt my stove (thanks Elk) and after the stove rebuild my problems only got worse due to the stove working more efficiently, which meant it lowed my exhaust temps.

    My stove top temps were always 500 and higher with the Vigilant and the wood was bone dry seasoned hardwoods of over two years stored on concrete.
  14. North of 60

    North of 60 Minister of Fire

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    Ahh yes now I get it . Self cleaning is a positive consequence alright. Must keep her spik and span. Have you thought of a patened yet? Sounding better all the time Rumme.
    Bob B stick with Struggle on this one. ;-)
  15. GaryS

    GaryS Member

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    Looks familiar. What size is your stove pipe? Is it 8" also? I had the same problem. The goop was more water than creosote. I put in a 6" SS liner which was the same dimension as the stove pipe and my problems ended. I also am burning better wood this winter.

    Attached Files:

  16. rumme

    rumme New Member

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    no offense, but your post makes you seem like a condescending XXXX.
  17. rumme

    rumme New Member

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    Oh...by the way, not that its any of your business, but I do have a U.S patent on 1 invention and 2 other inventions with a patent pending .

    any more wise ass remarks ?
  18. begreen

    begreen Mooderator Staff Member

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    Let's not divert from the OP's concern here folks. Stay on topic.
  19. rumme

    rumme New Member

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    I agree, other posters should not make sarcastic remarks about me or my situation.
  20. begreen

    begreen Mooderator Staff Member

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    runme, the two things I would check are first to be sure there is no air leaking into the flue from the cleanout door. Duct tape it on all seams and the hinge temporarily to check. The other thing I would do is not close the air all the way. Don't close it further than where the factory stop was before it was removed. That will keep the flue hotter.
  21. begreen

    begreen Mooderator Staff Member

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    Bob B. You need to get things warmer assuming that this is not a case of partially seasoned wood. Double wall pipe on the interior connector would help a bit. Burning a bit hotter might also help.
  22. humpin iron

    humpin iron Feeling the Heat

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    chimney block construction is just about the worst thing you can use. No clean out=wrong, dead head chimney=wrong, thimble pitched toward living area=wrong. Sounds like you should tear it out and start over.

    I assume it's an old Defiant, if so that is a very large heater, needs about 2-2500 sq ft for where you live. Sounds like this is in a basement, stv is probably running way too cool with less than seasoned wood, hence the water content. You may have to look at replacing the stove with a smaller EPA approved model.

    Liquid creosote like in your pics has 96 chemical compounds in it and is classified as a hazard waste in several states, this is a health issue for anyone living in the house.

    If your chimney pro came out and cleaned the flue, saw the wall and said all is well......you may want to replace him also.
  23. remkel

    remkel Minister of Fire

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    Nighbor had a condensation problem with his wood boiler that led to a chimney fire. Seems to me somehow your gasses are cooling in your run as others have suggested. His solution- stainless steel pipe with insulation.
  24. cmonSTART

    cmonSTART Minister of Fire

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    Sorry to hear about your issues, especially with a new chimney. I think it's going to take a bit of work to fix the issues. Minimum you should get a cleanout installed (interior). Honestly I think the best thing to do if you can is to install an insulated stainless liner. Tile liners are often cold and leaky. The idea with the stainless is to keep the flue gases as warm as possible and get them up and out quickly.

    Do as BeGreen suggested. Burn hotter if you can. This will help.
  25. LLigetfa

    LLigetfa Minister of Fire

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    cmonSTART and BeGreen offer sage advice. Reducing the moisture content of wood would only reduce the amount of condensate. After all, 20% MC in a hundred pounds of wood is still 20 pounds of water.

    Another, although lesser source of moisture is room air. This can manifest more where people store lots of wood indoors to dry. If the stove is provisioned for an outside air option, drawing dry outdoor air can reduce condensate as well. Moisture is the scaffold upon which creosote can build like snowflakes.

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