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not your grandpa's garn

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by TCaldwell, Jan 15, 2012.

  1. bpirger

    bpirger Minister of Fire

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    Loc:
    Ithaca NY Area
    Yeah, that's what I was wondering....If we are all seeing 450-550 on the flue temp, maybe we should have a little turbulator of some sort in there to scrub a little more heat. LIke a nice piece of steel 4" wide, heated and twisted, and about 3-4' long. It could be removed from the HX tube when cleaning right from the front.....


    SO we can buy this for Garn?

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  2. Sawyer

    Sawyer Minister of Fire

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    Shouldn't be difficult or expensive to have one made if one had a fabricator nearby or equipment to do it yourself.

    I have neither. :-(
  3. heaterman

    heaterman Minister of Fire

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    There's more to it than just a piece of metal in the flue. Martin went through more than a few designs until he found one that did what he wanted it to.

    Not saying that this or that might not show an improvement but you have to know what your looking for before you can shoot at it.
  4. Frozen Canuck

    Frozen Canuck Minister of Fire

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    North central Alberta, Canada
    +1 on having a plan before you begin. It did occur to me that you could do this "too good" a drive the unit into the condensing range & that would be a very bad & messy thing.
    Not saying "don't try" just encouraging a thought through plan first. I like & appreciate all the tinkering many of you do, just be a tinker with a plan is all.
    Good luck in your efforts of achieving 87.9999% eff. Hope you don't get to 88% or beyond.
  5. Sawyer

    Sawyer Minister of Fire

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    Understood Steve, perhaps smoking or gambling would be an easier compulsion to control. :)
  6. heaterman

    heaterman Minister of Fire

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    LOL

    Whoda' thunk that wringing the last bit of efficiency out of a wood burner could be so addictive.

    I think the key to an effective turbulator would be achieving turbulent rather than laminar air flow characteristics in the flue tubes. As far as the Garn is concerned I think that there are a couple reasons that the baffle is after the combustion fan rather than before.
  7. bpirger

    bpirger Minister of Fire

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    Ithaca NY Area
    According to Keith at Garn, $44 for the piece. I have asked if there is an average exit flue gas temp drop....I'll pass along what I hear. It is soon to reach the Parts section of the website.
  8. Sawyer

    Sawyer Minister of Fire

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    Northern WI
    Thanks for checking!

    -22 degrees, Garn cruising with a 400 degree flue temp.
  9. Jim K in PA

    Jim K in PA Minister of Fire

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    Hey Tom - just got back to Hearth after a while and am catching up. Glad to see you got everything up and running. I was hoping you would call me to come up and help with the setup after your move! I see the "skunkworks" is in full operation. Great job.

    After a while you get a feel for when the GARN gets "up on plane" so to speak. I know it's gassifying within 5 minutes based on the flue temp and the change in sound of the exhaust. Nice to see some empirical data confirming what I "feel".
  10. TCaldwell

    TCaldwell Minister of Fire

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    Hi Jim,
    I ended up doing the plumbing in stages, mostly after work also I barely fit behind the garn where most of the plumbing is located. I was thinking about the offer but realized it became a one small person job, thanks anyway. The major time consumer became the controller parameter set-up. I would do a burn, datalog and email file to cybosoft, they would evaluate trend and email parameter updates to load into controller for a new burn. All the wood was weighed to 60 lb for initial testing, and varied there after, some nights I got 2 burns in, others just one, this went on for about 6 weeks. At this point I am very satisfied with the controller performance and results, some latest combustion data,
    o2=6.6%
    excess air=45.1%
    co2=13.7%
    ppm co=320
    ppm coaf=468
    eff=86.4%
    sec burn temp=1580degf
    flue temp=264.2degf
    with my set-up these results are relatively consistent throughout the burn and repeatable from one burn to the next.
  11. Jim K in PA

    Jim K in PA Minister of Fire

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    So now the question is . . . what will you tinker with next? :)
  12. TCaldwell

    TCaldwell Minister of Fire

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    Well Jim, you know this is a addictive lifestyle! I actually have lot's to catch-up on, insulating pipes, getting ahead on wood ect.
    tom
  13. TCaldwell

    TCaldwell Minister of Fire

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    Loc:
    860-868-9014 h 203 948 0864 c nw corner ct.
    Jim, you know this 'hobby' is an addictive lifestyle! I actually have alot to catch-up on, insulating pipes, catching up on wood ect.
    thanks
    tom
    sorry for the double post

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