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Stainless Steel Chimney liner - when is it needed

6hadwen5 Member Posts: 2
Getting quotes to replace 27 y/o oil boiler in Maine. I have exterior brick chimney @ 25 y/o that has two terra cotta lined flues - one for my wood stove, one for my current oil boiler. Last Chimney inspection described both 8" flues as being intact w/ a hardened glaze on the inside of the liner. I have received quotes for 4 boiler options from two installers:

Viesssman VR-1 High Efficiency with Riello burner - flue temp 311 - 356 per tech manual
Penzotti dk2-4 with Riello f5 burner - - flue temp 350 per tech manual
EKS 2000 Model Ek-1 with Beckett Flame Retention burner - 300 per installer
Biasi Model B-10/5 with Riello Flame Retention burner - 350 per installer

The EKS is being quoted with a 5" Stainless Steel liner for my exterior brick Chimney with Terra-Cotta liner on 2 story Colonial in Maine. . I've been advised that because the flue temp on this will be lower than the Biasi the installer does not feel that I need the Stainless steel with the Biasi but do need it on the EKS. both sets of quotes are from experienced and well - established companies with years of oil boiler installs behind them.

1) Seems to me like a 50 degree difference in temp going up a 35' exterior brick chimney in maine is not a big enough temp difference and that whatever condensing issue would happen @ 300 degree exhaust to require a stainless sleeve would also occur (maybe @ a reduced rate) in a boiler with 350 degree exhaust.?
2) Conversly I am wondering if I'm being sold a liner that I don't need?
3) Is the other guy (who did not recommend a liner) missing something that I should have installed and if I'm going to end up putting one in later or paying for chimney damage if I don't install it on the other boiler options.

Can anyone point me to any data that shows when this would be need or not needed?


  • cableman
    cableman Member Posts: 69
    edited October 2016
    Im justs a diy'r but i would want a liner for both the wood stove and the boiler. I installed an insulated 304ss liner for my wood insert and my boiler has a 316 ss liner.
    The boiler liner stays rather clean while the wood stove liner builds up alot of soot.
    Clay liners get old and crumble and i think these apliances work better with the correct size flue all the way up.
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,453
    It depends on a lot of factors, there is no standard rule that a 350* net stack temp won't produce condensation in a masonry chimney. A 35' tall brick chimney containing two 8" square flues is a quite a bit of mass and if fully exposed would probably need a liner. I'd also recommend you look at the sizing of the boilers.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    Solid_Fuel_ManSWEIdelta T
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,499
    What @Robert O'Brien said about boiler sizing as well.

    I'm in northern maine, and in my experience with both wood and oil, any exterior chimney needs an insulated liner. With any of the boilers you choose, condensation will occur at least at the top of the chimney. Sulfuric acid from oil condensate is not nice to masonry.

    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • 6hadwen5
    6hadwen5 Member Posts: 2
    Thanks for the input everyone.