Came across this flue with several mini size holes in the flue. They were actually at both units in the attic. Anyone know what this could be from. Not sure how to describe this and the appropriate amount of weight to add to the issue. Grateful for any feedback. Thanks.
It looks like the pipe was laying around in the truck and got damaged, considering the damage near to it. If it were just by itself, I’d think maybe a rodent.
There should be zero exhaust gasses leaking into the interior of the building envelope.
That said, on the scale of stuff to freak out about, this ain’t it. It should however be properly sealed or replaced.
Some high temp epoxy or furnace cement to do it properly.
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Flue damaged, causing possible exhaust gas leak into home. I wouldn’t try and “weight” it necessarily. If you mean should it be called as a defect, in my opinion, yes.
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Improper flue piping!
That is cheap, thin, vent pipe for range hoods, etc… NOT appliance exhaust flues!!
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I thought it looked more like flexible b-vent. But that brings up a good point, the holes may only be in the outer jacket.
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The service tech that goes out to repair it is either going to ignore it or wipe a dab of high-temp silicone on the holes. No chance it gets replaced.
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Non-issue in my opinion. Those small holes are no different than the HVAC tech probe holes. If the flue is venting properly, air would be sucked in rather than exhaust gases leaking out.
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That’s what i was thinking to
Gotcha. That’s what I was especially curious about
Thanks Ryan. You probably get this in summaries after the inspection. “So does it just need a repair or are you saying an hvac guy needs to come out here and start replacing parts. And does it need to get fixed immediately due to some health risk? Etc.” Always like to know how to respond appropriately in those conversations
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Were you able to determine if it was double wall B-vent? If so, the urgency of repair slides down a bit (assuming the holes weren’t through the inner section as well).
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Yeah. Flex B-vent. Couldn’t tell if holes were only on exterior though.
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I would write it up as a safety concern. And in my opinion, all safety issues need immediate attention.
I would not slice and dice this thing or spend a lot of time on it. Just write it up.
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Good eye. I’m thinking that material might be made further up the supply chain and is also used for the outer layer of b vent. Or they all have the same aluminum forming machinery?
zoom in on that first page of the document ryan shared. its a similar pattern
It would be surprising to have a sub par vent here. This was a track home in a nice neighborhood from a 2009 build. Installing a bathroom or kitchen vent for the furnace flue would open up the builders to lawsuits with everyone in the neighborhood right? 
It looks like a single wall flexible vent connector, not a cheap, thin, vent pipe for range hoods as others suggested. The problem with them is they could condense in a cold attic, If you’re in a warmer climate, it may never be a problem.
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What are the flues servicing? I see posts about B vents. What did the exterior flue termination look like?
Either or.
Mechanical damage. If it is a B vent, just because the outer shell is likely damaged with punctures does not mean the inner flue shell has not be punctured or damaged.
As well, fastened upstream flue collar is reduced in diameter.
I would, refer a licensed NG HVAC contractor further evaluate and repair immediately.
Disagree. Never, ever…see probe holes in the flue. The obvious reason is that on a 80% furnace/boiler, the flue gases rise naturally out of the flue. On a cold day, the warm combustion gases have to push the cold air slug at the top of the flue out. The gases will leak out of any holes in the flue until the flow of warm gases is established. That leakage rarely rises to the level of dangerous, but our tolerance level is zero.
Write up holes in the flue.
And add that to the report…“Appears to be a component not rated for this use”
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Not that simple. It has been confirmed, in the flesh; both single and double wall duct use that same material.
Here is a double walled connector:
And here is a single walled duct:
But I had a hunch all along… you can tell by the connector. the indent at the end is where the double wall stops, is it not?
I doubt many duct companies are vertical manufacturers. they buy this stuff from someone else and put it together.
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Good points.
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