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Wood Stove Rear Flue Exit?

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blueridge

New member
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. /|\
 
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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:

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Does that help?
 
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.
 
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! :)
 
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!
 
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.
 
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.
 
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.
 
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.
 
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Oh and using 2 45's instead of a 90 is good advice too. I did this with my new stuff and it was a big improvement.
 
blueridge said:
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.
Click to expand...


That is a tough question. Our straight out the back stove pipe was from a wood cook stove which did NOT draft very well, but it's like comparing apples and oranges; cook stove to regular wood stove. One advantage I liked with the S.O.T.B. method was the clean-out of the portion of the stove pipe inside the house was very easy. You can just reach your arm all the way in from the clean out access in the T outside the yurt wall.



On our double 90º stove pipe we actually have to disassemble the interior pipe once per year in order to clean out. Very messy and a lot more work, but I *think* it drafts better. Although it does smoke a lot when we open the door to add wood.



?
 
'Although it does smoke a lot when we open the door to add wood.' Have you tried opening the damper before opening the door to load?
 
Also, I found that if the dome is open at all, it lets more smoke in when I open the stove. Most of the time no smoke comes out when the stove is hot.
 
We even crack to door to let it start burning really hot before adding wood. This does help, but I think the two 90's are probably to blame. We also open a window first or close the dome. Try to change the pressures... Oh and we have fresh air intakes in the floor as well AND a very long insulated chimney.



Do yurt people actually have wood stoves that DON'T smoke when you add wood? I had kind of given up on the possibility...
 
Takes a while to learn how to run your stove. I have an old 80s era air tight stove in the center of the yurt, with a pipe that runs straight shot from top of stove up through the ring. It just doesn't get any better than that in terms of draw.

I load the stove through the front by opening double glass doors. When adding wood to a cool stove that's been running damped down to low, with both doors and the flue damper closed, I open the damper, then crack open the doors and let the fire wake up a bit. That would pretty much eliminate smoke entering the yurt when the doors were fully opened to load., unless the wood was damp from rain or snow.

When stoking the stove running hot, doors open, damper open, even damp snow covered or rain soaked wood generally didn't smoke the yurt. Plus I'd get maximum heat. If it did smoke inside a bit, partly closing the doors would increase the draw and get the smoke drawing back inside, and get damp wood to blazing. Took awhile to learn how to run the stove so it didn't smoke.
 
Another thing, all three of my yurts were drafty. Lack of air flowing into the stove from a tight yurt wasn't a problem. lol If my yurt was primary dwelling, I would have an exterior air supply piped into the box, just like I do for the fireplace in our house.
 
Hello , first off heat is omni diertional, but not straight up, it will always go to the cold and most likely you have already proven that, when you sit at the campfire you feel the heat even tho you do not sit right ontop of it the ground under the fire is warm as well, now that out of the way the out the back was created because some people think stove pipe are ugly to look at , and you have more cook surface on top with the vent in back but you can take it straight out the yurt wall to your T, or if you want more heat bring it up above the stove, and then out the wall, it will not matter, just what ever you like but if you bring it up then you can get one of those fan for the pipe to push more warm air in the ger/yurt, but remeber its your yurt and what ever you decide is the correct way,


enjoy your ger/yurt
 
Jafo how does hot air move or radait out from a fire heat always goes to the cold and it does not care how it gets there up down looped to looped heat period will always go to the cold, unless you send it by some means
 
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