I need a pep talk. Getting discouraged with new Jotul Oslo...

I hope that post did not come out wrong, my point being I was surprised they said a 8x8 was OK due to the fact the round liner is supposed to be a better choice, we all know under the right conditions a 6 inch schedule 80 piece of pipe works great for a stove pipe if installed correctly.

Your post was fine.

It's always been a bit confusing to me as well. I think the main thing to realize is that 8x8 (7x7 ID) square clay tile will contain the same volume as 8" ID metal pipe per linear foot, and the hot flue gases will expand to fill that volume, dropping temperature and pressure as they do. I don't really believe the interior corners are exempt from this pressure drop, so the flue should have equivalent venting capacity. All I can say is that it works for me, but it wouldn't be my choice for a stove with a 6" outlet.

What is perplexing to me about my installation is that is necessitates the use of an 8" round thimble. An 8" clay thimble has an ID of just a little over 7", so I need to reduce my 8" pipe to 7" in order for it to fit into the thimble. This creates a bottleneck of flue gases just as the pipe enters the thimble. My IR gun shows an increase of almost 100ºF right at the reduction. From this observation it is clear to see first hand the effect of pipe diameter on temperature. Of course, on the other side of the thimble, the gases expand and temperature and pressure drop once again as the gases enter the larger volume of the square flue.

If I was to have a brand new chimney built, I would check out a cast-in-place liner. They are supposed to be more durable than SS liners and superior in insulating ability.

http://www.hickorymountain.com/old_files/gfliner.html

BK I like that, I wonder if I can do that inside my 7 1/4 inch round liner.

That is interesting, BK do know what that costs? I am in no hurry, but it is good to know about it.

Koko said:

Figured I'd give an update a little over a year later. This past summer I had a mason (friend of the family) come and add 4' to my chimney. The brick matched perfectly and I also added a chimney cap finally.

Well it made a night and day difference. My draft is worlds better. I have to close the intake shortly after lighting a fire and I have a nice bed of coals. Needless to say the extension was cheaper than the liner. If it didn't work, I was going to add a liner this year (2012). But for now, I see no need. I also did not have to add any insulation below my thimble inlet in the chimney. It's drafting fine without this. It's much more enjoyable this winter because it's less work.

I also have seen the light on dry wood. I'm hoping by next winter I'll have a couple cords in reserve seasoning.

Click to expand...

Good to hear Koko, and nice to see you again here! I havnt forgotten our (other site) conversation! I'll shoot you a message with the details later, but I plan on a spring purchase for 2013/14 winter. Also, about the wood I bought off your guy last year, man that stuff is tricky! I saved roughly a quarter cord all summer (from last winter) and its still a PIA to get going real good! It does well once going, but takes a good hour to light off even in a good coal bed.... Its like he stored it in a pond lol!