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Vent supports for PVC venting

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Big Ed_4
Big Ed_4 Member Posts: 2,788
in THE MAIN WALL
Looking for a good support or bracing for a boiler PVC venting / intake rung up a prefab type chimney ? What do you use for bracing the weight and securing the termination ?

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    Stand back, she gonna grow!!!

    Thar she grows! 1.1" per 100' length per 10 degree F difference.



    Aye, usually support it in tip using uni strut and strut clamps, and let it float free on the bottom.



    Unless of course you want to drive your customer crazy with the tick, tick tick of expanding plastic :-)



    If I MUST support it mid length, to avoid side movement, I will sleeve it with the next larger pipe so that it is stabilized, but can still expand and contract through the sleeves.



    ARRRrggggh. Got bird poop in me eye, and took a swipe to wipe it out, and put my eye out with me hook. AAARRRRGGGGGggh... ;-)



    ME

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  • icesailor
    icesailor Member Posts: 7,265
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    PVC Exhaust Venting:

    Aren't the PVC pipe manufacturers starting to dis-approve of PVC exhaust venting?

    And some boiler manufacturers like Veissmann do not allow the use of PVC in their exhaust venting and it is illegal in Canada. Only the UL and ULC listed and approved CPVC. And will PVC exhaust venting turn into Ultra Vent or Plex Vent?
  • Big Ed_4
    Big Ed_4 Member Posts: 2,788
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    expantion

    Expansion noise is a good point , Thank you.,Mark I never thought of it Hmmm I can forget about bringing up the air intake ,I can not see two 3' pipes through a 7" chimney with being two tight .

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    Doesn't matter WHICH plastic you use Chris...

    And this battle has been going on since condensing appliances were born. PE, PB, they ALL expand and contract and must be compensated for.



    ME

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    Use Lochinvar Knight...

    I'm telling you, THIS company listens and responds.



    Some time ago, I proposed to them that in retrofit situations that it would be ideal to use teh annulus between an existing old style vent and the plastic venting system to allow the incoming combustion air to pick up additional "free" heat and make the job of venting much simpler. It is in their most recent I&O manual. They are the ONLY manufacturer (to my knowledge) to allow this excellent practice. I am certain that others will follow shortly.



    As long as it is a straight shot to the roof, no problem. If there is an offset, could be a problem....



    Thanks Lochinvar!!



    ME

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  • tim smith
    tim smith Member Posts: 2,760
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    Re intermediate supports in chimney for pvc

    We have used stainless hose clamps not to tight under couplings at mid points, usually 2 or 3 depending on ht of chimney. We then put small 1/8" or less dia stainless cable through hose clamp and loop and cable clamp. Hang out top of chimney with cable and drop down. Then we pin down top of cable with tension on it to take weight off vertical run. We have had 3 to 4 sets of cables on long vertical runs at top of chimney. Then we strut clamp at top and bottom with strut brackets taking support also.  Works very well.  If a long chimney, we do this but also change to stainless vent as it is much lighter for a long run.
  • icesailor
    icesailor Member Posts: 7,265
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    Venting:

    So, could you put the two pipe part of a concentric vent system into the chimney flue and then switch to single pipe?

    On another note though, in my experience of years of looking at brick work and poorly constructed flue ways, I wonder how the make-up air will end up. If you use a Veissmann Vitodens and use a concentric vent kit, they insist that you check the air intake port at the top of the boiler for CO levels to show if there is any contamination from improperly connected exhaust piping.
  • CMadatMe
    CMadatMe Member Posts: 3,086
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    ASTM 1785

    Anyone that installs a condensing boiler that flue gas temps exceed 140 fail the standard period. No argument about that. The scope of the standard clearly states that. So every person that installs PVC venting on a system that has an indirect of curve bangs off 180 is responsible for the vent.



    Read the installation manuals. The mfgs all list this standard but that also state that it is the installers responsibility to make sure the pipe is being using in an application to the standard. It's not giving contractors a green light to vent with PVC at will. That's why they list the other standards that AL24C, CPVC, ULC-S636 meet. I attached my case.

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  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited April 2011
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    Double Post Sorry

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