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Do I really need a chimney liner?

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Dean_7
Dean_7 Member Posts: 192
I'm just a homeowner but this is what happened to my chimney. This chimney originally had a clay liner when the original boiler was coal fired it was fine, when the original boiler was converted to oil in the late 1950's it was fine. However the original boiler was converted to gas in 1980. At the time another liner was installed making the chimney smaller but it was ordinary single wall galvinized vent pipe. The damage you see here was caused by moisture in the flue gasses condensing at the point the chimney penetrated the cold attic space. The consensus is the acidic nature of the moisture formed by the condensing gasses ate the liner up in a few years and proceeded to attack the chimney itself completely destroying it. The chimney ended up being dismantled there was no way to save it. I found the original instructions for the gas conversion burner and they recommended a stainless steel liner be installed. obviously the directions were not followed.

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  • Steve Garson
    Steve Garson Member Posts: 191
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    Do I really need a chimney liner?

    I was reading the instructions on my new WM SGO-4 and noticed that it says that if your chimney has three exposed sides, then you should install a chimney liner, regardless of the chimney condition. My chimney tile liner is in good shape. Do I really need to pay for a liner? Will the burner need to be readjusted after a liner is installed?
  • Firedragon_4
    Firedragon_4 Member Posts: 1,436
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    Heating guys are

    exceptional at what we do, FACT!

    But, a chimney requires another type of professional, call one of these people: www.csia.org




    www.firedragonent.com

  • Dean_7
    Dean_7 Member Posts: 192
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    liner

    I'm just a homeowner but this is what happened to my chimney. This chimney originally had a clay liner when the original boiler was coal fired it was fine, when the original boiler was converted to oil in the late 1950's it was fine. However the original boiler was converted to gas in 1980. At the time another liner was installed making the chimney smaller but it was ordinary single wall galvinized vent pipe. The damage you see here was caused by moisture in the flue gasses condensing at the point the chimney penetrated the cold attic space. The consensus is the acidic nature of the moisture formed by the condensing gasses ate the liner up in a few years and proceeded to attack the chimney itself completely destroying it. The chimney ended up being dismantled there was no way to save it. I found the original instructions for the gas conversion burner and they recommended a stainless steel liner be installed. obviously the directions were not followed.
  • Jack_21
    Jack_21 Member Posts: 99
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    Yes, you do!

    you just got a nice new piece of equipment and they are TELLING you what you need to make it last, efficient and trouble free. I would go to WM and ask for the minimum size that you can re-line with. For this you will need to know the height of the flue, the length of the vent connector, firing rate, overfire draft. You may be able to use a smaller liner.
  • Bob Harper
    Bob Harper Member Posts: 1,040
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    think you don't need a liner?

    Answer this question: Can it perform its intended function?
    Is it sized to fit the appliance? A brand new chimney can need a liner due to sizing. Most do.
    Is the flue intact ALL the way? Is it impervious to heat, moisture, and erosion? You say the tiles are in good shape-- did you run a ChimScan up the flue or are you basing this on your visual inspection? You can properly see about one tile joint in. After that, you're guessing.
    -is this type of chimney problematic for this use? Cold, exterior chimney? A lot of exposed surface area? Northern climate? Other appliances sharing or solo?
    -what do your codes say about chimneys? NFPA 211 is referenced by , UL,ASHARAE, NFGC, NFPA 31 (oil), and many mfrs. Does your chimney meet NFPA 211?(Answer is No). What does 211 tell you to do about changing an appliance if it is another fuel type or of a different efficiency? (Do a Level II inspection). You will not pass a Level II inspection.

    I'd like someone to show me a chimney that is not already relined that does Not need a liner.
    There are both legal and practical considerations to this. If you want that equipment to give the the stated performance, it needs the set of lungs it used during the testing, which was not some crummy masonry chimney.

    As for Weil Mac Gold boilers, don't push the undersizing of the liner. While the charts may indicate a smaller liner will work, don't go more than one half size. W/M's need larger liners to breathe properly. Pain in my butt... Figure it out for yourself. The firing rate would indicate a 5" liner but they use a 7" collar to the draft hood that reduces to a 6". On this one, don't go below 5.5" liner. Try to get a 6" down.
    HTH,
  • S Ebels
    S Ebels Member Posts: 2,322
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    I'd line it without a doubt

    In the first place you flat out need a liner. Period. The flue temp is not high enough to keep the gases from condensing in your chimney. I've seen good tight chimney's that are all interior eaten up in a matter of 3-4 years.

    In the second place, your present chimney is probabaly not sized correctly for the volume of flue gas your boiler now puts out.

    Thirdly, look at it this way, the cost of lining your chimney is far less than tearing it down after it rots out and starting over from scratch.
This discussion has been closed.