Help identifying chimney pipe

[sbb]

Hey, first post here. Great forum, I've enjoyed reading and learning so far.

I recently purchased a place with a wood stove. The stove is a couple decades old, but everything looks in excellent shape except the last 12" length of chimney that mates with the cap. At some point this section must have been damaged by snow. Upon further inspection, whoever repaired it previously left me with a fire hazard, as this last section of double-wall chimney is missing the inner wall. It's also too short for my roof (which is what prompted me to look in the first place, glad i did!). So I'm looking to replace this section with a 36" section of straight pipe, which will also get the cap at the height it needs to be for my roof.

I'm not having any luck identifying the original manufacture however. I've spent hours searching, looking at images, old manuals, old manufactures and I just can't seem to match it. The identifying stickers have faded and are no longer readable other than a faint "UL Listed".

ID: 6"
OD: ~9"
Distinguishing characteristics:
6 detents/tabs pressed in where it couples
8 vent holes on the flanges

I'd be grateful if anyone can put me out of my misery here with what should be a simple replacement. Since the rest of the system is in great shape, firebox in the attic, stove pipe, everything appears to be solid, my plan is to only replace this section of pipe at this moment, if I can locate a suitable replacement. The sticking point is that 9" OD. There are plenty of manufactures that have a 8.0 - 8.2" OD and Duravent has a 10" OD in their triple line, but I've found nothing with a 9" OD.

Note: the photos are of the damaged section I intend to replace, that's missing the inner wall.

 

[willoweep]

It’s Metal Fab. Does it have an aftermarket chimney cap? If the insulation that’s exposed in the coupler gets wet, it can cause the spot welds that hold the liner to fail. Consider a storm collar if you don’t have the factory Metal Fab cap

 

[begreen]

If that upper section's insulation got soaked, then it's possible the lower section's did too. It may be time for replacing the chimney pipe.

 

[sbb]

Thank you! I believe you're right on all counts @willoweep. I was too quick to dismiss Metal-Fab because I must have an earlier tooling version of the flange, but all the other design attributes appear to line-up, most critically the 9 in OD. I went ahead and ordered the section and feel optimistic I can make it work.

Does it have an aftermarket chimney cap? <<
Ah! you're on to something. Yes the cap is aftermarket, and it does NOT have a storm collar. The cap doesn't have any sort of flange either, so water ingress is possible. That's all plausible why the liner failed. At some point the stack must have been knocked off the roof due to snow loading. The chimney cap is pretty beaten up too. If the spot welds were worn, I bet an impact with the ground would be the time the liner shakes loose (and maybe why the liner was misplaced when someone put it back on the roof). It's a solid theory.

I had planned to replace the chimney cap because it lacks a spark arrest and is pretty beaten up. All the more reason now. The DuraVent DuraPlus looks like a good option with a spark arrest, has a lip to help divert water, and significantly less expensive than anything else. I'll likely add a storm collar too after size everything up.

@begreen thanks for the heads up on the lower section. I'll give it a more thorough inspection, especially knowing now that the spot welds are a weak point. Hopefully I can get a few more years out of it before full replacement. My home purchase decimated my near-term budget so I'm trying to get through a winter or two if everything else looks adequate -- and I'd like to save up to get a pellet stove for another heating project down the line (fingers crossed)