Need help reducing from 8” chimney to 6”.... sort of

[bruh44]

I had a chimney liner installed a few years ago. The dumbasses that did it for some reason thought I needed an 8” chimney, so that’s what I got. At the time I didn’t think it made a difference.
I have a Hearth Stone with a 6” pipe. What I found is that I can’t get it above 350. It just won’t hold temperature. I was thinking of adding a damper right behind the stove at the top of the L shaped elbow. I also found a 8 to 6 reducer that looks like I could just drop it in at the top of the chimney. Does this sound like it would be effective?
my chimney is about 35 feet tall.
If you have other recommendations, pictures, or even places to order from would be very helpful.
Thank you all in advance!

 

[Ctwoodtick]

If the installers installed the wrong size pipe, I’d demand they change it to the correct size at their cost. As a homeowner, you shouldn’t have to compensate for a faulty install.

 

[begreen]

There are multiple questions/issues here. Why would the damper be added right behind the stove? Is draft too strong? Is that also the reason to reduce pipe size at the top? Is there a thermometer on the stove pipe above the elbow? If yes, what temperature does it run at?

Another typical reason for low stove temp is partially seasoned firewood. Have to ask, if just to eliminate this possibility. How long has the wood seasoned after it was split and stacked?

 

[bruh44]

I use a mix of wood. But even using wood that has been split small and dried for two year, I can’t hit 400. The chimney is inside a solid masonry chimney, so no thermometers on the stack.

 

[Highbeam]

Which hearthstone? Sounds like a stove fed from a liner and tee in the rear?

35’ of 8” pipe is a drafting monster. You could suck seagulls off of a landfill! You’re surely way over the specification and adding a key damper is a step in the right direction. I would have a damper even if it was 6” pipe.

I had a hearthstone heritage for many years and it takes forever to heat up even when everything is proper. It looked great and burned clean though.

 

[begreen]

Yes, that is my thought, but I don't want to assume too much. At 35' the stove could be basement installed in a negative pressure zone. It would help to get some clarifications on the specifics.

Specifically, how is the stove connected to the chimney?
What Hearthstone model stove is this?