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3 screws in the flue collar?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by bag of hammers, Oct 10, 2012.

  1. bag of hammers

    bag of hammers Minister of Fire

    Joined:
    Jan 7, 2010
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    1,168
    Loc:
    Northern ON
    Hi all. I have stove with @ 6' of double wall black pipe - straight up from collar to chimney (adapter). No screws in the flue collar at this time.

    Heating season upon us, so as I clean the stove / chimney, check things over etc. I'm once again wondering about the flue section. I've done a quick search in the forum here and this is what I gather -

    3 screws in flue collar are most often intended to address a single wall pipe connection - may not be the case for double wall flue connection, especially if the double wall pipe sits securely in the collar (i.e. takes a lot of force to get it apart), and flue is on top (not rear).

    can someone please sanity check this for me?

    I confess I've burned a couple seasons like this. The reason I haven't added the screws (beyond the fact I almost need a come-along to pull the pipe out of the flue without them) is that the exposed part of the collar is literally only about 3/4 " (the collar is actually deeper, but the Osburn 2200 has a "heat shield" on top where the trivet sits, which hides most of the collar). It took about 20 minutes to work / pull that pipe off the collar last time (e.g. when I had to move the stove to install a hearth pad). I actually thought I would have to crush the pipe to get it free.

    I can't imagine how I would be able to get a drill on the collar, let alone at anywhere near 90 deg to the pipe, from anywhere except from the back of the stove. The need for screws everywhere else to keep the sections from coming apart is a bit more obvious to me, but what are the odds that any separation would happen right at the flue, i.e. the pipe lifting up and right out, especially with an extremely tight fit like this?

    II don't recall seeing any pre-drilled holes in the collar before putting the pipe on. So I'm looking at going thru the steel collar which is probably @ 1/4".

    Any thoughts / advice are appreciated....

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  2. Highbeam

    Highbeam Minister of Fire

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    base of Mt. Rainier on the wet side, WA
    They aren't needed at the flue collar with a vertical double wall install. I asked and was ridiculed (slightly) by the inspector when I had my permit finalled out. Also notice that you can't put screws in at the ceiling support box either. You do need to lock the slip joint apart with screws which prevents the whole mess from going anywhere.
  3. bag of hammers

    bag of hammers Minister of Fire

    Joined:
    Jan 7, 2010
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    1,168
    Loc:
    Northern ON
    Thanks Highbeam for the quick reply. So if I understand it correctly, the inspector advised against them (sorry you got ridiculed a bit - it would be nice if all the approved stove manuals made this really clear). The slip joint is another interesting point - I thought of the slip as a way to allow the pipe to expand a bit without stressing the pipe or lifting the weight of the chimney when it heats up and stretches a bit - but everywhere I asked the advice was to lock it down, as you said.

    btw - I want a toy like the one in your pic..
  4. Highbeam

    Highbeam Minister of Fire

    Joined:
    Dec 28, 2006
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    8,878
    Loc:
    base of Mt. Rainier on the wet side, WA
    You can't screw through the double wall pipe into the collar without crushing the outer wall anyways and up top, there is nothing to screw into but if you don't lock the pipe telescoping section from collapsing then the whole mess could fall down quite easily. Everybody says 3 screws at every joint and that is fine with single wall but not double wall. Not sure how you could even screw single wall into the ceiling support box joint.

    I spent a couple of hours smoothing a neighbors field last night. It hasn't rained here for almost three months and it is a major dust bowl. The whole machine was brown. My lungs too!
  5. bag of hammers

    bag of hammers Minister of Fire

    Joined:
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    1,168
    Loc:
    Northern ON
    Very nice of you to help out your neighbor. Hopefully you had a chance to wash the dust down with a cold brew. Thanks again for the help here...

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