Flexible liner weight support

[Mijoka]

I will be installing 36' of flexible liner. Because the chimney design gradually becomes narrow in one direction and wider in the other direction as it approaches the roof line, the top six feet will be a 4" x 10.35" oval section connected to the 6" round. The round will be pre-insulated but the oval section will not be because of space restrictions. I was told this assembly will be in the 70-80 lb weight range. This liner will be getting pulled up from the bottom with a hand cranked winch setup because of the chimney design, weight & length. I have concerns about properly supporting the weight of the liner. This is a brick unlined chimney and the top courses are stepped out a bit, leaving small horizontal shelves on the inside of those top three courses. I thought I'd attach some 14" long flat stock to the liner on the long sides of the oval and then rest them on some steel rods going from the shelf on one side to the shelf on the other. I figure that will support the top end so I can unhook the winch cable and pulling cone. The liner will then stick up through the oval collar of a stainless steel full chase cover and the collar and liner will be connected with stainless steel screws . The bottom termination will be a tee. Assuming that all works out, do you think I should clamp some support legs on to the tee to take weight off of the top connections?

 

[bholler]

I will be installing 36' of flexible liner. Because the chimney design gradually becomes narrow in one direction and wider in the other direction as it approaches the roof line, the top six feet will be a 4" x 10.35" oval section connected to the 6" round. The round will be pre-insulated but the oval section will not be because of space restrictions. I was told this assembly will be in the 70-80 lb weight range. This liner will be getting pulled up from the bottom with a hand cranked winch setup because of the chimney design, weight & length. I have concerns about properly supporting the weight of the liner. This is a brick unlined chimney and the top courses are stepped out a bit, leaving small horizontal shelves on the inside of those top three courses. I thought I'd attach some 14" long flat stock to the liner on the long sides of the oval and then rest them on some steel rods going from the shelf on one side to the shelf on the other. I figure that will support the top end so I can unhook the winch cable and pulling cone. The liner will then stick up through the oval collar of a stainless steel full chase cover and the collar and liner will be connected with stainless steel screws . The bottom termination will be a tee. Assuming that all works out, do you think I should clamp some support legs on to the tee to take weight off of the top connections?

Screws through the top plate into the liner are not enough to support that much liner. And going to oval at the top especially uninsulated sounds like an absolutely horrible idea that will lead to plugging at the top very quickly

 

[Mijoka]

Screws through the top plate into the liner are not enough to support that much liner. And going to oval at the top especially uninsulated sounds like an absolutely horrible idea that will lead to plugging at the top very quickly

This stove will be burning anthracite so I was not overly concerned with creosote. It is going to oval at the top or nothing because of the existing chimney design. The cross section of the oval is larger than the cross section of the 6" round, so while the air flow pattern may change, there is no size restriction. I was thinking of stuffing some ceramic insulation around the liner where it transitions to oval and use pour in around the top 6'. My main concern is the weight support and oddly that does not seem to be a much discussed issue when I search online, which I found odd. For that matter, suppliers of chimney liners do not seem to mention liner weight. Perhaps they are afraid to scare off DIYers.

 

[Mijoka]

This may appear elsewhere but thought I'd post the link because it addresses what size oval liner to use with a particular diameter of round pipe. It appears to not only be a product of matching square inches of cross section but also the minor dimension of the oval. https://www.rockfordchimneysupply.com/blog/oval-liner-table/

 

[bholler]

This stove will be burning anthracite so I was not overly concerned with creosote. It is going to oval at the top or nothing because of the existing chimney design. The cross section of the oval is larger than the cross section of the 6" round, so while the air flow pattern may change, there is no size restriction. I was thinking of stuffing some ceramic insulation around the liner where it transitions to oval and use pour in around the top 6'. My main concern is the weight support and oddly that does not seem to be a much discussed issue when I search online, which I found odd. For that matter, suppliers of chimney liners do not seem to mention liner weight. Perhaps they are afraid to scare off DIYers.

Ok so coal changes allot. You need to run heavy wall 316 liner if you want it to last long at all and 36' it's going to be well over 100 lbs. But if you use the proper top plate and clamp rivet the top clap fast it will be fine. And you just want to pull it up through the top plate