Vacuum Leak at flex liner connection

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Kvic

New Member
Sep 12, 2021
96
Middle Tn
Was recommended to check the connection at the flex liner for leaks. I did and found about 3/4" area that was drawing in flame from a lighter. After posting in my other thread took info from the reply, and checked again with an incense stick, no fire and just the door open a couple inches. Found another section about 1 1/2 to 2" area that was drawing in smoke. Attached a photo with the areas highlighted. The left side is actually the larger area. Started this thread since it's not brand specific or buried in the other thread.

Can I use mill pac black to seal these areas, or is there a better way to do it?

[Hearth.com] Vacuum Leak at flex liner connection
 
Was recommended to check the connection at the flex liner for leaks. I did and found about 3/4" area that was drawing in flame from a lighter. After posting in my other thread took info from the reply, and checked again with an incense stick, no fire and just the door open a couple inches. Found another section about 1 1/2 to 2" area that was drawing in smoke. Attached a photo with the areas highlighted. The left side is actually the larger area. Started this thread since it's not brand specific or buried in the other thread.

Can I use mill pac black to seal these areas, or is there a better way to do it?

View attachment 290112
I would think some thin stove rope gasket could be put in the gap. You could likely get it from a local stove shop. We’re you having issues with the gap?
 
I would think some thin stove rope gasket could be put in the gap. You could likely get it from a local stove shop. We’re you having issues with the gap?
Having issues with cat overheating. Looking at all possibilities and was suggested to check for leaks at the connection, and found them. I think if I used rope insulation I would have to put it all the way around. If I just try to fill the gaps I think it would create more gaps.
 
Having issues with cat overheating. Looking at all possibilities and was suggested to check for leaks at the connection, and found them. I think if I used rope insulation I would have to put it all the way around. If I just try to fill the gaps I think it would create more gaps.
Probably not a big deal to put it all around the liner connections. Can’t imagine you make it totally air tight with the corrugated liner, but probably a bit better. Don’t be forceful with it. Don’t want to slip and damage the liner. Maybe gently pack it in with a dull flathead screwdriver.
Maybe one of the pros here can give you more info about why your cat is overheating.
Honestly, I’d wait until you get more opinions on this from others. Don’t want you take an unnecessary step.
 
If this is a new stove install with a new cat, then I can say that it's normal to have new cats overheat.

Second a leak after the cat won't affect its temperature. It may cool down the flue gases, which is bad, so it's good to look at. But it won't resolve cat issues, and if this is a new cat, it doesn't need to.
 
Furnace cement will help some but gasket is the best fix if it will fit. But as others said a leak after the cat like that would reduce cat temps if anything
 
Thanks for all the replies. Wasn't sure how it would affect the stove, but wanted to be sure.

Yes it is a new install and still getting used to it. I understand from others on the forum that new cats can be overactive, just had some concern of getting to 2000 and over on the cat probe. Only able to burn intermittently due to lack of seasoned wood, so maybe taking longer for it to settle in. Will look for some rope insulation to see about sealing the gaps.
 
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