7" stainless steel liner with 8" wood stove

I have an old Timberline wood stove & the chimney is over 30 feet high. The stove started having smoking issues so I had it cleaned (there was lots of creosote!) and they discovered cracked tiles in the chimney. They are going to install a stainless steel liner, but we have encountered many problems. The opening on the back of the stove is 8" and they where planning on installling an 8" oval liner (flue is oval). The liner cracked during the process (it is not as flexible as a round liner and they did not have the proper equipment to handle the job). It also caught on something protruding inside the chimney about 5 feet above the thimble area. They gave me two options. Cut an opening in the back of the chimney, clear the obstruction and pull a new 8" oval liner down the chimney or attach a cone with a rope on a 7" round & pull it down - no need to cut an opening in the back of the chimney. They assured me the chimney is so tall that going down 1" in diameter would not cause draft problems. Well, the 7" caught in the same place. Now they are telling me that they will have to cut the hole to install the 7" round. They suggested a 6" round might work without cutting a hole, but I think that is too small. My question is do you think a 7" round will work okay with an old Timberline 8" since the chimney is very tall? They said it should be fine. To install the 8" oval, they would need a bucket truck to hold up one end while the other one is pushed down inside the chimney. Otherwise it will bend too much and crack. The 7" would definitely be easier to install although both require cutting an opening in the back wall. This is my first wood stove. Will a 7" liner work okay with that stove? Also, if I bought a more efficient stove in the future, would I be able to find one that works with a 7" liner or is that an odd size? Any information would be greatly appreciated. Thanks!

You should never down size the liner on a wood stove. If it calls for 8" you should use 8".

If you are thinking about a new wood stove in the future, most likely it will use 6". So you have some decisions to make. Is purchasing a new wood stove now an option? You could save money on installing a smaller liner but have to buy a new stove. Also the new stove will be more efficient than the old one you have now. This means a lot less wood consumption.

It sounds like you might want to get another opinion. I'm not sure these guys are very good. It's pretty hard to crack a liner. Is there any reason they didn't remove the clay liners? The SS liner needs to be insulated because the clay liners are busted, are they insulating? In order to get the 8" down, the clay will have to be removed. The 7" will likely work OK, but there is no real way to know until you spend the money. Like James said, you might consider a new stove. Most hearth stores will make a pretty good deal when you buy a stove and a liner.

They removed the tiles. The oval liner was bent over so far that it started to unravel. They are going to put in the stainless steel and then pour an insulation material around it. Would the height of the chimney help with the draft of the smaller liner? The guy said that was one reason the smaller liner will work. He wouldn't on a shorter chimney. Also, he said that he preferred round to oval. If we go with an 8", it has to be oval. I really can't afford a new stove right now but maybe one day.... Thank you so much for responding to my post so quickly!

Uh oh, that sounds scary. I have had oval liners bend over to far, they do not unravel, they kink. Things aren't adding up, liner unraveled, want to use a smaller liner than required, I would get a different company in there at least for an estimate.

X2

Yes, height does should affect sizing. I would do the 7" round before the 8" oval. A 7" at 30' will have approximately the same draft potential as an 8" at 15', +/-10%. There all kinds of poor sizing problems with wood stove flues and specs so take it with a grain of salt. The wood stove industry is the only one I have ever seen that does not do actual flue sizing.

I'm not sure what you mean here?

6" insulated flex liner, at 30 feet you should be fine.

I suspect that the 7" would work just fine. I have a 5.5" insulated liner that is 25' tall running my 30. I'm far from the only one with this setup.

Before I had another liner go down it, I think I'd be trying to figure out what it's catching on. There is no sense catching another liner in the chimney.

Matt