Combi exhaust vent yellowing

Robbi

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!

hot_rod

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

Nice sheetrock access :)

Robbi

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

Is this the flexible Centrotherm venting system?

Robbi

https://forum.heatinghelp.com/discussion/comment/1828512#Comment_1828512

Yes - duravent from supplyhouse

pedmec

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

GGross

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