Jotul F100 Clearances with Double Wall Stove pipe and "extra" heat shield?

[Nate R]

Trying to understand pipe clearances for my particular stove.

The F100 can be set up for a top exit or rear exit stove pipe. My intention is to do a corner/45 install, and I'd like to do a rear exit into a Tee, and then straight up through the scissors truss and sticking out of the roof ~7 feet. I'd like to use double wall stove pipe to have low clearance to the wall going up.

Jotul's Manual says: Use of double-wall pipe will require installation of included Flue Collar Heat Shield in order to meet the minimum combustible wall clearance. See page 12 for clearance specifications.

They mention this in 2 or 3 places in the manual, and have pictures of it, etc. They explain that this is needed to keep wall clearances OK, and double wall pipe means the flue temps are hotter at the exits.

What I don't understand: Do I need this shield installed somehow in a rear exit situation? Nothing in the manual says "Double wall with top exit needs this shield," it just implies the shield is to be mounted with double wall, period. How do I know clearances are OK on a rear exit without this shield? Or, how do I install it sideways or behind a Tee?

Thoughts on how you'd approach this?

 

[moresnow]

Why not use telescoping double wall in a top exit config? Looks like you will have a short pipe setup due to the corner install/roof line. Skip the 90 is my opinion to alleviate potential draft issues on a minimal length vent sys.
Efficient looking layout. Bath must occupy the lower right? What drawing/cad program are you using? Nice detail.

 

[Nate R]

Why not use telescoping double wall in a top exit config? Looks like you will have a short pipe setup due to the corner install/roof line. Skip the 90 is my opinion to alleviate potential draft issues on a minimal length vent sys.

We'd really like to utilize the rear exit, partially to have some useable space on top of the stove for heating water, food, etc.

I'd argue that the gases have to make the 90 either way in the F100....They are running above the baffle horizontally at the top of the stove, so they need to turn 90 degrees to go up the top exit, or turn 90 degrees inside the flue in a rear exit. The short length is another reason I want to use double wall to begin with. Still though, we'll end up between 14-15 feet total length to cap from the exit.

Efficient looking layout. Bath must occupy the lower right? What drawing/cad program are you using? Nice detail.

Thanks! Actually, it's a dry cabin. Lower right is an enclosed entryway that will get a bench, hang coats, etc. Bath is the fan-vented outhouse a 30 foot walk from the cabin. Drawing: just using floorplanner.com, which is mostly free, some other options in it are cheap.

Edit, adding a pic of the cabin...so far.

 

[moresnow]

Nice! Enjoy.

 

[EbS-P]

I don’t see how that flue collar shield could be installed in any useful manner with a rear exit. My complete amateur understanding is the double wall let’s you set the stove closer to the wall the collar is not insulated so it needs shielded if you set stove at double wall clearances. With rear vent stove will be far enough away from wall to meet single wall clearances thus not needing the collar shield.

Have you seen the F100 in person? The top is big enough for a kettle and a small skillet top vented. I would value my floor space more than the cooking space (top versus rear vent). I would add the hearth pad to your cad drawing to get a good feel for how much space it will take up.

Evan

 

[Nate R]

Evan, thinking through what you said, I think that's gotta be it, double wall in a rear exit, the stove itself is already far enough from the wall so that it doesn't matter.

I have definitely seen the F100 in person. Have it sitting in the cabin now. Yeah, we could fit a small kettle or skillet in top vent, but wanted to have the full top accessible. This couple has a rear vent setup on their F100, and you can see it gives them better room to cook on, like cupcakes, etc. https://www.ourtinyhomestead.com/our-wood-stove.html

On the other hand, I hadn't looked at the floor space difference with rear vs top vent. I set up clearances in my drawing. To unprotected walls, I need 10" from the corners. So I put 10" boxes in the drawing, and then added the stove pipe tee dimensions, and added 6" boxes between that and the wall, and a 16" box from the glass for hearth protection sizing. I found that with the F100 at 10" clearances from the corners, I already have enough clearance/room behind it for the double wall rear vented. So even if I were to top vent, I'd be taking the same amount of floorspace. So no space lost going rear vent double wall...interesting! I also then looked at the minimum non-combustible pad/floor size I need...Looks like 46x46" at an absolute minimum. I was anticipating 48" or so anyway, so I think I'm fine there.

So, that settles it for me, I can just set the stove at 10" (or a bit more) from the corners to the finished walls, and then set the double wall stove pipe location from there, and I should be good. Thanks for making me think about it a bit differently, and that forced me to see if I'm giving anything up by sticking with rear exit.

 

[EbS-P]

I think that about covers it all. It is interesting you don’t loose any floor space either way. I just assumed the T connection would move it out further. Looks nice.