Deteriorated flue pipe!

[Trent Tarter]

This was one of the most deteriorated flue pipes I have ever seen.

[Jim Luttrall]

Wow! Was this on an old flue pipe converted to a newer unit requiring a smaller flue? I see corrosion from this quite a bit but never like your photo!

[Bob Harper]

Single walled vent connector used as vent in unconditioned attic joining upper and lower sections of B-vent it appears to me.

[Jim Luttrall]

Single walled vent connector used as vent in unconditioned attic joining upper and lower sections of B-vent it appears to me.
After a closer look, I agree with your assessment. I did not catch that at first glance.

[Trent Tarter]

Yes the deteriorated portion is single wall pipe, and yes it's oversized from an older system most likley. I am recommending that the whole thing be repacled from furance up. I don't know about you guys but this is the worst one I have ever seen. There was also had some exhuast fans venting in attic that were close to the flue pipe, CO was probably being pulled back through them when furnace was operating.