Wood Stove Rear Flue Exit?

[blueridge]

Hello from central VA!

I've had my yurt for ~7 years now, a 24' from Laurel Nest. I have a mini-split as the main

heating

and cooling system, but am getting ready to add a wood stove as a supplemental/alternative for below freezing temps. I've been studying Jafo's excellent write-up on The Yurt Chimney thread and will use that as my guide. I have a couple questions, but will start with this one:

The stove we have is a little Jotul F100. It has the option of top or rear flue exit, currently with the flue collar on the back. This is the configuration my wife prefers. I have yet to see a picture of a stove in a yurt using a straight rear exit going straight out the wall to the T, then up the chimney. Is there a reason other than the exterior flashing having to be extra tall to slip under the roof? I am new to free standing wood stoves. (Grew up with inserts and masonry chimneys, and have a pellet stove insert in my house.) Is there something I am missing or don't know about? Does anyone have a rear exit? Experiences to share?

I appreciate your time. /|\

[Jafo]

Not sure I follow you 100% but my pipe goes through the wall, then then T's there. The cleanout is right at the bottom of the T:



Does that help?

[blueridge]

I will try to explain better.
What I’ve seen most often on rear exit is it going immediately to an elbow, going well up above the stove, then another elbow to head through the thimble and to the T.
What I am asking is if instead you can go straight out the back of the stove and through the thimble just slightly higher than the exit point on the stove, and into the T. Does that make sense? The second way would eliminate the two 90 degree elbows, but the T on the exterior would be just slightly above level with the rear exit point on the stove as opposed to higher up the wall.

[Jafo]

Oh I gotcha. I have never seen that myself but we are getting a little out of our area of expertise here. I would like to recommend the forum at http://www.hearth.com. They are very knowledgeable and have helped me a few times.

Let me know what you find out!

[blueridge]

Thanks for your response and pointing me in the right direction. I will let you know what I find out.

[pablo]

Hey blueridge. We used the rear exit of our waterford cookstove and went straight out the side wall about 3 feet above the yurt floor. We did not slip the metal flashing up under the yurt valence. However we cut flashing such that all the edges tended to land on a piece of lathe for secure connection with roofing screws. With the flexible steel flashing the connection was very tight and sealed very well to the yurt fabric. We also put in a layer of silicone just to be safe. That worked for us for 20 years with no leaks.



In our latest incarnation, I cut out a square piece of yurt fabric (from a new window we installed) a few inches bigger than the flashing. Cut a hole in the square for the stove pipe to pass through and used 3M adhesive to glue this 'patch' to the yurt sidewall and flashing. It is very water proof and looks much nicer than flashing alone. LMK if you want a pic. Hopefully I am making sense. Need coffee!

[Bob Rowlands]

Jafos install is the way I'd roll. Pipe horizontally out the stove, through the wall, into the 'tee', and then up. The whole business anchored to a rock solid stack support. In my view one tee is a better design then two ells and a tee.

[Pacific Yurts]

Doing a rear exhaust from the stove straight through the wall and into the cleanout tee rather than top exhaust and a 90 to go through the wall can safely be done. We normally recommend penetrating higher on the wall to allow the exterior flashing to slip under the top cover valance and act as a "shingle" without the need of any caulk. Penetrating lower on the wall would require applying a bead of silicone caulk along the top edge of the exterior flashing prior to screwing it into position, but should work fine.

[blueridge]

Thanks for all of your thoughts and comments. I posted my question on Hearth and the thread is still generating conversation. Here's the link in case anyone want to follow along.


It looks like it essentially boils down to these pros for each:
- Straight horizontal exit out the wall to the T: 1 less 90 (less resistance), longer chimney for the same height on the yurt
- Switch to top exit: easier to waterproof by tucking flashing under roof lip, easier to change stoves in the future with different heights.

The question for which there doesn't seem to be consensus is if the rear exit straight through the wall would have a worse draft on start-up, especially in combination with the shallow fire box. I would sure love to see into the future before I cut a hole in the wall.

[Jafo]

I would think the straight out the back would have a worse draft simply because heat rises. Going out the top is better IMO.

While you're planning, also consider an outdoor air kit. I did that with mine and it definitely helps with drafts in a yurt.