6" to 8" new insert

[Toddppm]

Just found a nice Lopi Freedom to replace my old Black Bart insert. Old insert is maybe 30+ yrs' old and defintely not airtight. Hopefully I'll get a lot longer burn times and use a little less wood.
Problem is, I installed a 8" liner for the old insert couple years ago and it works great for that stove but the new has a 6" flue opening. How much of a problem do you think I'll have just using a coupler to go from the 6-8? Not going to cost much to experiment with it, already found a reducer at the store on the way home if it works good I can order a good stainless one to replace the cheap metal later. Just wondering if anyone has done this as I know you shouldn't go from 8 down to 6 but haven't read anything about going bigger?

 

[turnkey4099]

Just found a nice Lopi Freedom to replace my old Black Bart insert. Old insert is maybe 30+ yrs' old and defintely not airtight. Hopefully I'll get a lot longer burn times and use a little less wood.
Problem is, I installed a 8" liner for the old insert couple years ago and it works great for that stove but the new has a 6" flue opening. How much of a problem do you think I'll have just using a coupler to go from the 6-8? Not going to cost much to experiment with it, already found a reducer at the store on the way home if it works good I can order a good stainless one to replace the cheap metal later. Just wondering if anyone has done this as I know you shouldn't go from 8 down to 6 but haven't read anything about going bigger?

That's basically what I have except my big chimney is larger ?10"?. Causes creasote to deposit as teh larger chimney doesn't heat up enough. Not a major problem though.

HarryK

 

[jasult]

would think it will be just fine but keep eye on the draft being strong when you try the first burns from scratch

 

[beerbelly]

I have an antique oak stove. 6" exit pipe on stove. 8" thimble into an 8x12 chimney. I have not had any problems. But I agree with the "chimney never gets that hot", so I do have some build-up. I check it often & sweep it when I need to. It does draft very well, so I need to keep the stove shut down most of the time. My house is also very small, so I heat myself out if I let it get to hot anyway. I hope this helps you. Good luck, check the chimney often.

View attachment 275709

 

[Toddppm]

Before I put the 8" liner in the old insert was just vented into the clay flue, I think around 10x16"? So it drafts like a freight train compared to that.
So my draft will be reduced a little right? Or do I have that backwards?

 

[Streblerm]

Before I put the 8" liner in the old insert was just vented into the clay flue, I think around 10x16"? So it drafts like a freight train compared to that.
So my draft will be reduced a little right? Or do I have that backwards?

Your draft will be reduced a little vs a 6" flue but it will be better than into the 10x16 flue.

I would check out the instruction/install manual for the Lopi you want to put in. It will specify the maximun size for the flue. I have a similar install. I ran 8" double wall stainless flue for my old stove but the new stove says it can vent into a 10" square flue or smaller down to 6" round.

 

[stihly dan]

Or at least reduce the top to 6 as well. Should work better.