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Chimney Lining

Scott Gregg
Scott Gregg Member Posts: 187
If you don't the condensing flue gasses may very well eat out your terracotta liner and cause water damage to your home at least, CO poisoning at worst.

Line it.

Comments

  • B Mac
    B Mac Member Posts: 3
    Do I line the chimney?

    I just removed my old hot water oil boiler and installed a Buderus natural gas fired boiler (82.1%). My installer said I did not need to line the masonry chimney but others are telling me that I should. My home is brick and is approx. 70 years old but has what appears to be a decent terracotta liner. Any advice would be appreciated.
  • JeffD
    JeffD Member Posts: 41


    Line it.
  • Jim Eastman_2
    Jim Eastman_2 Member Posts: 27
    Chimney liner

    If your existing chimney has a clay tile liner and it is in good shape, I don't see any need or requirement to install a liner in the chimney for an new atmospheric boiler with an AFUE of 83%. The key word is "good shape"! If the existing "terra cotta" clay liner is cracked and damaged, you will have to install a liner.

    Jim Eastman
    Marmot Heating
    Niwot, CO
  • The correctest answer to your question is, \"That all depends\"

    If the combustion rate of the new appliance matches the venting as to size then liner material and condition will determine whether or not to line. If the firing rate is less than the area that the existing vent presents then you have to line the chimney in order to reduce its volume. An oversized vent will not allow your new boiler to operate optimally.
  • B Mac
    B Mac Member Posts: 3
    Chimney Liner

    Thank you for your input.
  • Constantin
    Constantin Member Posts: 3,796
    Totally agree...

    ... first determine if the extant flue is the right size - your professional can determine that with the help of the boiler specs. Many chimney flues originally built for coal and wood fires are grossly oversized for todays weatherized homes and lower-output boilers.

    For example, our old flue had an approximate 12" square opening, our new boiler requires only a 6" round opening, or about 4x less area. If the flue is oversized, you may not get a good draft going and may also face condensation issues in the chimney. My personal preference would be to line the chimney with a smooth-walled, high-quality stainless liner.
  • Dan Goodridge
    Dan Goodridge Member Posts: 62


    Line it!
  • RTB
    RTB Member Posts: 8
    look in the boiler book

    It may call for a 5" or 6" chimney (flue size) - area of round chimney is 3.14 (Pi) x radius x radius, so 5" is about 19.6" area, 6" is 28" area, 10 x 10 liner (inside, as an example)is 100". All that extra volume sucks up heat, so the moist combustion vapor turns to rain half way up. Acid rain. Then it runs down. And eats what it touches until its acidity is used up.
    Also, that extra volume cuts efficency. You'd save a bit of money.
  • JackFre
    JackFre Member Posts: 225
    If you check the tables in NFPA 54

    you will find that it must be re-lined. maonry chimneys are excellent architectural devices but poor mechanical devices. You are using 11th century technology to vent 21st century equipment. A liner on that type system will promote easier light offs and fewer puff-backs. It is a new system.
  • Anthony Menafro
    Anthony Menafro Member Posts: 200
    Line it!

    You should line it for the above said reasons(sizing) and because the new efficient gas boiler flue gases will be wetter and with the heat will then dry the mortar and cause it to fall out. When safety it a consideration and causes you to ask a question, chances are that you should go the extra yard.It's your safety at risk.
    Anthony
  • Paul Pollets
    Paul Pollets Member Posts: 3,666
    Line It!!

    Our local codes call for chimney liners, even if there is a clay or terra cotta liner. The new boilers require venting designed for the appliance. While an aluminum Z-Flex liner will work, an insulated liner using stainless steel will give better performance and last longer. Yes, this adds cost to the project, but you'll get the same answer from Buderus. Improper venting will shorten the life expectancy of the appliance.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • RTB
    RTB Member Posts: 8
    chimney is stainless, 20 yr old-i KNOW it needs resizing

    the question is, can you reduce a stainless insulated chimney with a 5" liner - one chimney guy on the phone said "no way," and I want to know whether it is possible, if the condition is okay, etc.
    The boiler calls for 5", and the pipe is adapted UP to the 8"chimney pipe.
    wisdom as to getting it done, suppliers, etc is what i need, or tell me it's impossible and must be replaced.
    Thanks
  • Tom S.
    Tom S. Member Posts: 94
    approx cost for lining?

    I'm just curious what a (very) approximate cost of putting in a s.s. liner into a masonry chimney might be. $1k, 2k, 3k?

    I was talking with someone the other day who suggested it might cost $2800 to line my chimney and that seemed like a pretty high number.

    Thoughts? Just looking for a ballpark figure.

    Thanks

    Tom
  • B Mac
    B Mac Member Posts: 3
    approx cost for lining?

    I received a quote of $3k to install a s.s. liner into a masonry chimney.
  • Tom S.
    Tom S. Member Posts: 94


    Thanks - that is right about what I heard, which is still a lot of $$, but safety first....
  • sinkdoc 43381
    sinkdoc 43381 Member Posts: 6
    Chimmney

    Line it
  • Bob Harper
    Bob Harper Member Posts: 1,099
    salient points

    The homeowner stated the chimney appeared to be ok. This is a layperson making an uneducated opinion about a sysetm he can't see. I don't care who you are, you cannot see what you need to see more than a few feet down a chimney. Before installing new equipment, you are required to get the chimney inspected for suitability of the intended appliance. The national standard for chimney inspections is NFPA 211. This std. calls for a Level II inspection, which can include video scanning or digital photography. However, this is seldom needed because either end of the chimney almost always fails. A 211 compliant chimney is a unicorn--they don't exist in the wild. The chimney must be suitable for the class of service. Venting a high efficiency boiler such as the Buderus is a recipe for condensation. You use an aluminum liner, you'll be replacing it in just a few yrs. You need a high grade stainless steel such as AL29-4C or 316Ti. Most importantly, the liner must be sized to the appliance. Even if the chimney was brand new, that Buderus would require a liner simply for sizing.

    I see a trend in the HVAC industry where the mind set is still thinking about a liner only when someone bugs you about it. You should be trying to justify when NOT to reline! Otherwise, the point is moot.

    HTH,
    Bob
This discussion has been closed.