Prefab Chimney Disaster, Need Advice!

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Member
Nov 20, 2020
8
US
Hi all! I hate for my first post to be half complaint half clueless, concerned flailing for answers, but here goes!

Bottom line up front: I have a 1/4" gap on one side between the interface of a 2 ft slip fit termination section of pipe at the very top of my factory built chimney, the termination section slides about 3" down into the top section of chimney pipe. The 10" outer pipe around the 8" chimney is completely intact. Is this a major safety concern? (two certified sweeps I had look at it say no, one says yes)

Long story even longer:

About a month ago I had a chimney sweep/repair (certified chimney sweep, member of the chimney sweep guild) company come out and replace my chase cover for my factory-built, wood-burning fireplace. It is built into an exterior chase.

After having the chase cover replaced my normal chimney sweep (certified sweep, member of the chimney sweep guild) come out and clean the chimney. They noticed that at the very last section, part of the termination cap of the chimney, there is about a 1/4" gap on one side between the last section of 8" chimney pipe and the slip-fit termination section of 8" chimney pipe. They said it was wrong, unsafe, and I should have the company that did the chase cover come out and fix it.

So I had the company that did the chase cover come out, they took a look, said it was fine, everything they took off went back on as they had found it. Funny thing is, my normal chimney sweeps never noticed this before. So I called YET ANOTHER chimney sweep (certified etc etc) to come perform an inspection. Their guy came out, spent about 30 - 45 minutes taking the termination section out, slipping it back in, checking around at the top of the chimney after taking pictures from inside. At the end of it all he says it is likely good to go, safe to burn, and calls his boss to ask just to make sure. Boss okays it and they give it a clean bill of health. Both of the companies said it was probably like that since I owned it, and my wife and I used it about 6 times per season, but I don't see how it wouldn't have been noticed before this.

At this point, two companies who took a close look said it is okay to burn, but they also definitely acknowledged there is about a 1/4" gap on one side between the top sections of pipe. My normal chimney sweeps, who refused to even come out to inspect it again close up but saw that there is a gap, continue to say it is not safe to burn and that I must get it fixed.

What do you folks think? At this point no local place that installs pre-fabs will touch it or help me with parts. So at the going rate for things around me I'm looking at $4500 - $5000 to replace the whole system. Awful steep for something that only provide ambience....
 
Has anyone provided you with pictures of the issue? Why was a slip joint used at the top of the chimney instead of a fixed-length?
 
The first picture is a picture just with my phone looking up the chimney. You can see in the lower portion where the line of light is visible between that top slip fit section and the rest of the chimney pipe.

The other pictures are looking down into the chimney (sorry, due to some technical difficulties these ended up having to be a picture of my inspection camera screen) between the 10" and 8" pipe, where the top section interfaces with the rest of the chimney. This is the portion where that gap is showing in the first picture. This is at about the top ~14 - 20 inches of chimney.

If it's actually original, I believe a slip joint was used because it was a valid option as one of the termination caps when the fireplace was originally installed. There was an option to either run chimney pipe out of the top of the chase and attach a raincap OR there was a "telescoping" termination cap that included a section of chimney pipe on it. Of course in the 27 years the home has been around, a previous owner could have ripped out a fixed length and done what we have now... I've owned the house for just over 2 years. Prior to this I did not have any work done on the chimney, just inspections and cleaning.

[Hearth.com] Prefab Chimney Disaster, Need Advice! [Hearth.com] Prefab Chimney Disaster, Need Advice! [Hearth.com] Prefab Chimney Disaster, Need Advice! [Hearth.com] Prefab Chimney Disaster, Need Advice!
 
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bholler any thoughts on this? I'd be inclined to replace it with a fixed 24" length if the pipe is still made, but not if it isn't a problem.
 
As an update, I am currently burning in it. I have a ladder set up to check the chase cover, etc. Chase cover is nice and cool, 10" pipe is warm, no unreasonably hot air flowing out of it, 8" pipe is hot hot hot (as expected) with very strong draft. Will continue to monitor.

Going to kick myself if the chase ignites, but it's a wet day and I'm watching closely. I anticipate the worst part to be if I have to put the fire in my fireplace out and the draft isn't strong enough to pull everything out of the chimney.

Look forward to see what folks think, but in burning a fire for the past hour it seems to be functioning okay. Not very long for heat to build up yet, though.

I agree with your inclination @begreen, currently having trouble finding a company to sell me the section of chimney. Even though the part numbers are the same, they say using them on older systems still compromises the UL listing. Looking at this top section the UL listing was compromised long before I arrived on the scene.....
 
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bholler any thoughts on this? I'd be inclined to replace it with a fixed 24" length if the pipe is still made, but not if it isn't a problem.
I agree with you
 
Would there be a massive issue with securing a fiberglass/non-combustible high heat rope gasket around the end of the slip fit section such that it centers the pipe and closes the gap? If this is completely idiotic please just say so, I know very little about chimneys.

Do you have suggestions for where I might be able to source the chimney sections? Heatilator still makes them with the exact same part numbers, so I can't imagine they are radically different from what they were around 20 years ago. In fact, they even make a model of fireplace that looks nearly identical in the technical drawings and everything.

The burn yesterday had absolutely NO problems after going for about 4.5 hours. The relative heat of everything seemed normal. No heat on the chase cover itself, the 10" outer pipe was warm to the touch, and the 8" pipe was hot. What little smoke there was seemed to only be exiting the 8". Outside was fairly humid and not particularly cold, probably mid-40s most of the day.