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  1. #1
    Join Date
    Aug 2008
    Posts
    35

    Default Why line chimney?

    I understand it is safer and more efficient. Just for knowledge reasons I am asking. We converted to natural gas and lined the chimney. The old boiler had about 3 feet of vent pipe. It went up 2 feet and elbowed 1 foot into the brick chimney that went up the center of the house. When we first moved in I installed CO/smoke alarms in every room that the chimney traveled through just in case of cracks or leaks in the chimney walls. When we converted I was told natural gas must be piped up the chimney. I'm curious is co from natural gas different from co from oil? isn't carbon monoxide the same either way? Would have every one in the house slept "very well" if you know what I mean if we had vented the new boiler the same as the old?
    Last edited by rwhnze; 11-12-2008 at 04:54 PM.

  2. #2
    Join Date
    Aug 2007
    Posts
    1,131

    Default Re: Why line chimney?

    The exhaust from an oil-fired burner is hotter than the exhaust from a modern day NG appliance. NG also contains more moisture. Hence more condensation inside the the chimney...which if made from brick and mortar...means trouble sooner or later. And that will be expensive trouble when it happens; more expensive than lining the chimney in a timely fashion. (There are also corrosive/acidic by-products from burning NG that can devastate simple brick and mortar chimneys..which this article doesn't really cover. Still..it covers the basics.)

    http://www.hutchschimneyandstove.com/1130166315/

  3. #3
    Join Date
    Aug 2008
    Posts
    35

    Default Re: Why line chimney?

    Thanks for the info ****hiller. That was a very informative article. I was told from a neighbor (when i found coal in the soil in my yard) that they used to burn coal for the boiler many years ago and they buried the unburnt coal in the yard. That makes lining the chimney that much more important. Hmm, now learning about the acidity of the exhaust will it have an effect on my roofing shingles years from now? The boiler takes air in from outside the house and vents through a PVC pipe 36' straight up and out my chimney with a screened "T" at the top. Also the boiler has a drain that condensation drains into. How damaging is the boiler drain to the house drain system. All the plumbing has been replaced with PVC and Copper but it is still cast iron where it goes through the foundation. Would the acidic water have any effect on the cast iron sewer pipe?

  4. #4
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,843

    Default Re: Why line chimney?

    With PVC flue you have a high efficiency boiler. The flue gas is low temp compared to the old system this does not supply enough heat to get proper draft for a large chimney. If you didn't have the liner installed the flue gases would never make it out the top before they cooled and dropped back down the chimney. With the proper sized flue the exhaust will exit the top with enough heat to rise and be carried away. The condensate should cause you no problems.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  5. #5
    Join Date
    Aug 2008
    Posts
    35

    Default Re: Why line chimney?

    Thanks for all the info. Seeing that it runs through the center of my house I'm glad to know that my chimney may last a little longer now.

  6. #6
    Join Date
    Aug 2007
    Posts
    1,131

    Default Re: Why line chimney?

    Yup. Sounds like you're good to go the way things are.

    Not to worry about your shingles as they'll be fine as regards exhaust gases.

    Condensate from furnace is of no concern to your plumbing either......as already mentioned.

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