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Do I need to Insulate Pellet 4" Flex Pipe on Exterior Chimmney?

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by johnny88, Aug 13, 2008.

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  1. johnny88

    johnny88 New Member

    Joined:
    Aug 13, 2008
    Messages:
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    Loc:
    Central, MA
    Planning on installing a Pellet insert into an existing Masonary Fireplace. Going from the insert 3" out to a 4" T connected to
    25' of 316T flex liner 4". The chimmney is in good condition but is on an exterior wall. I had a wood burner in it with just a 6' flex pipe through the damper opening and just past the inner clay tiles. The draft was very good.

    I don't know if I'm getting information mixed up with wood inserts and pellets. My question. Will the flex pipe all the way to the top, with a sealed blockoff plate and of course chimney cap be OK on an exterior chimney?

    Thanks - I'm brand new to pellets

    enviro empress

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  2. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Nov 18, 2005
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    28,645
    Loc:
    Northern Virginia
    With the positive draft from a pellet stove exhaust blower you are fine without insulation. With the negative draft of a wood stove chimney you insulate to keep the interior temp of the pipe hot enough to maintain draft and keep escaping moisture in the wood from creating creosote. The pellets contain a lot less moisture than cord wood.
  3. johnny88

    johnny88 New Member

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    Loc:
    Central, MA
    Oh boy! I know if I google, I'll get every type answer in the world. Positive vs negative draft.???? I think on a wood stove you want the draft to PULL out smoke and keep the chimney warm so creosote does not form. I guess on pellet since no creosote - no need for warm chimney. But would it still need a good dRAFT?
  4. kinsmanstoves

    kinsmanstoves Minister of Fire

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    Kinsman, Oh 44428 Brookfield, Oh 44403
    With an insert the liner is the way to go, all the way up. Another option is to go through the existing chimney wall and use a through the wall kit. depends what you want the vent pipe to look like outside vs having it hidden inside the chimney going all the way up.

    Eric
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