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Combi exhaust vent yellowing

Robbi
Robbi Member Posts: 22
in THE MAIN WALL

Hi. My combi boiler exhaust vent is beginning to develop yellowish orange streaks on the seams of the vent pipes. Attaining a proper pitch is impossible in my home due to layout etc. Would a 90 degree elbow help with the ventilation? Thank you all!

20241221_173025.jpg
20241221_173035.jpg

Comments

  • hot_rod
    hot_rod Member Posts: 24,592

    Probably leaking at that transition coupling? If that is the proper coupling there must be a seal inside?

    Nice sheetrock access :)

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    EdTheHeaterMan
  • Robbi
    Robbi Member Posts: 22
    https://forum.heatinghelp.com/discussion/comment/1828452#Comment_1828452

    Definitely the proper coupling - the inner seal looked fine. I'm thinking turbulent zone in that area and some of the exhaust is condensing onto inner ridges inside that portion in photo, and leaking downward. Just unsure how to solve - thinking introducing elbow with non corrugulaed inside

    Lol sheet rock - it was like that when I started doing my thing

  • Derheatmeister
    Derheatmeister Member Posts: 1,607

    Is this the flexible Centrotherm venting system?

  • Robbi
    Robbi Member Posts: 22
    https://forum.heatinghelp.com/discussion/comment/1828512#Comment_1828512

    Yes - duravent from supplyhouse

  • pedmec
    pedmec Member Posts: 1,173

    That yellowing is probably the lubricate changing color. Could be from heat, absorbing moisture, or aging

    GroundUp
  • GGross
    GGross Member Posts: 1,429

    When used for a flue the flex is not supposed to run at greater than a 45 degree angle ever. that's probably not what is causing the yellow, but somewhere in there you are probably trapping condensate as it can't run back to the boiler at that angle and will get trapped in the pipe

    Derheatmeister
  • Robbi
    Robbi Member Posts: 22
    https://forum.heatinghelp.com/discussion/comment/1828980#Comment_1828980

    I'll change it to a 45 degree and gradually work towards a gentler curve. The installation area is impossible to get the proper pitch to drain back to the boiler. Thanks for looking out

  • GGross
    GGross Member Posts: 1,429

    That won't help if it eventually runs horizontal , because that would be greater than 45 degree angle. Only vertical runs with the flex, its meant to drop down a chimney, they adapt to hard pipe before any bends. The 45 degree allowance is just to allow some maneuvering down a chimney, if you do a 45 degree, followed by another thats still a 90 degree angle.

    Derheatmeister

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