Scary crap, over fire or defective part?

[nola mike]

Had a pretty significant overfire a few weeks ago. Checked out the stove, no cracks or warps, didn't think anything more about it. Lately noticed decreased draft. Checked my key damper and felt "stuff" in there when trying to turn it. Figured it was the perlite/thermix insulation, so took the stove out, reached up into the liner, and felt a gaping hole above my block off plate. Removed the block off and found that the liner connector had failed at the straps, which I assume were spot welded to the connector. Pretty scary stuff. Is it possible that the heat could have melted the welds off, or is it more likely that the welds were defective? I don't like that I had to remove my block off plate to see the damage. If the insulation hadn't fallen into the chimney I don't know when/if I would have noticed it. Going to contact the liner manufacturer and get a new connector. I'm thinking of putting some sheet metal screws through the straps. It's impossible to put my plate above that joint. Thoughts/suggestions?

 

[webbie]

SS rivets.
My guess is that the spot welding was defective......spot welders are quite subject to being off a bit in terms of voltage, time, cleanliness of surface, etc.

McMaster-Carr and other such places have ss rivets.

 

[begreen]

How did the stove make out? Did the back crack? Definitely pop-rivet the connector for peace of mind. Our True Value carries SS pop rivets.

 

[nola mike]

I'll need a riveter. Going to call the liner vendor tomorrow to see if they honor the warranty. If they don't, you'll all know who it is I'm disturbed because this never crossed my mind as a possible failure point. Stove was fine on my initial inspection. Going to go over it closer now that it's out.

 

[nola mike]

Wow, that was fast! Called the liner supplier (royal chimney). Tech agreed that the part sounded defective, and that those spot welds shouldn't fail. Sent me the new connector, got it today. Also said that although the welds could fail, he hasn't seen it. So I don't know if the rivets are necessary on the new part. Tomorrow I reinstall and give the stove a good once over. Great customer service from royal chimney.

 

[nola mike]

Well, we're back up and burning. Close inspection of the stove, no damage. Only problem was the block off plate. Originally installed before I put durock/heat shields inside the fireplace. Proved impossible to put the shield back in correctly without taking everything out of the fireplace, which I wasn't in the mood to do. Not sure how much good it's doing anyway, since the chimney is insulated top to bottom with thermix. I may take it off altogether so that I have full visual access to all the joints in the chimney system.

 

[bholler]

That is why we always back up connectors like that with rivets I never really trust the band clamp connectors. On light wall liners you need to use washers with the rivets though or they wont hold.

 

[fire_man]

Do you add rivets to hold the T snout to the T? They use a welded band clamp to hold the snout to the body of the T.

 

[bholler]

no there is no way to do that and I have only seen a couple of those fail. I have seen the band clamp fittings like the one he had fail allot more as well as the band not being tight enough of loosening up over time ect. And regardless if we can back it up we will just to make a failure less likely.

 

[fire_man]

I was thinking of strapping another SS clamp around the snout.

What happened when the T snout failed? Seems like it would be a nightmare.

 

[bholler]

we replaced it with a new one which was a pain in the ass but it can be done

 

[fire_man]

What I mean is when it failed did smoke get into the house? If it fails while the stove is running it seems like it would be catastrophic.

 

[bholler]

The only times we saw it happen was in an install where the liner was insulated with thermix and it couldn't move much and the snout was mortared into place so there was not really much movement the homeowner didn't even know we saw it when we cleaned it and replaced it for them. That is how most of the liners we install are done if it happened in another situation It could be bad for sure I just havn't seen it yet.