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Viessmann and Matching Stainless to PP vent piping

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Simply Rad
Simply Rad Member Posts: 184
in Gas Heating
I have a 10 year Vitodens condensing boiler system I installed 12 years ago. The boilers are WB2A 15-60 units. I had to go with a 2 pipe vent system and used Fas-n-seal stainless steel venting. After 12 years the gaskets on a feel of the pieces have broken down and condensation is dripping out of a few joints. I have decided to replace the leaking fittings and adapt to PP venting materials. Today I attempted to replace the venting materials and when I installed the 4" PP pipe into the boiler 2 pipe adapter, I found that 4" PP pipe or 100 mm was too small for the 2 pipe adapter which I believe is 102 mm (according to the Viessmann venting manual. I really don't have any options other than use some RTV sealant? what do you guys think.

Thanks Jeffrey

Jeffrey Campbell

Comments

  • Ironman
    Ironman Member Posts: 7,376
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    I believe they make an adaptor, but I wouldn't recommend what you're proposing. Carbon monoxide poisoning is no joke.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Simply Rad
    Simply Rad Member Posts: 184
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    Something has to be better than the deteriorated gasket in the existing stainless steel venting.
    Jeffrey Campbell
  • Paul Pollets
    Paul Pollets Member Posts: 3,656
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    Adaptors are made, but each boiler will have to be separately vented
  • Simply Rad
    Simply Rad Member Posts: 184
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    Just figured out Duravent makes a 100-110mm vent pipe adapter. Its actually still used for a 2 pipe Vitocrossal CU3A
    2 pipe boiler adapter. I guess Europe uses thicker wall PP pipe 110 OD compared to north american 100 OD
    B)
    Thanks Jeffrey
    Jeffrey Campbell
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,006
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    Are you heating radiators? DHW?

    Just curious because those gaskets should have lasted longer.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • gennady
    gennady Member Posts: 839
    edited September 2019
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    You cannot mix and match venting material. It must be same from start to end. In NYC I cannot even install stainless steel termination from polypro kits.
    Heatfab and fast n seal SS venting always develop gasket issues with the time.
    Gennady Tsakh
    Absolute Mechanical Co. Inc.
  • Simply Rad
    Simply Rad Member Posts: 184
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    Alan the system is low temp radiant floor and DHW. When I spoke to Duravent they said that is normal life expectancy and 15yrs is max. Kind of a surprise to me. Gennady the vent is mixed to begin with. The vent is stainless, yet the boiler exhaust adapter is PP.
    Jeffrey Campbell
  • gennady
    gennady Member Posts: 839
    edited September 2019
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    Viessmann outlet is made of some plastic. Adapter is PP. innoflue and duravent have stainless steel terminations, yet in NYC having SS termination on PP venting is not acceptable, also you will not find adaptor to connect different venting manufacturers piping. I tried. Whatever starting adapter you have, determines what venting can be used.
    Gennady Tsakh
    Absolute Mechanical Co. Inc.

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