Hey everyone,
It's been a few years since I did this, but I've been using it a lot recently and thought I'd share my approach for installing a wood stove in my Grandby. It's probably my favorite feature of the camper now. I kept the LP furnace, but the quality of heat, the flickering light, and the sound (or lack thereof, compared to the furnace fan) from the stove make for such a cozy space.
The stove is the Cubic cub, and it has been awesome. It features a secondary combustion system that makes for a clean, efficient, and controllable burn. Definitely on the spendy side, but I'm a wood stove geek, so it was worth it for me.
IMG_20190209_133909643 by ben gibson, on Flickr
IMG_20181203_153842798 by ben gibson, on Flickr
Obviously, the challenge with our campers is how to install a chimney with a roof that raises and lowers. I opted for a straight chimney that could be installed and removed as needed, but another approach I considered was for the chimney to come out of the stove, bend 90 degrees to penetrate the wall, and then bend 90 degrees again upwards to clear the canvas. The outdoor portion of the chimney would need to be removable for when the roof is down.
I wanted my stove to burn as efficiently as possible, and there are a few issues with the above approach. First, the bends would impede flow through the flue, and thus through the stove, but also it's pretty well known that creosote and soot tend to build up at bends. I should add that these losses could be pretty minor, I never quantified anything...
Second, oxygen flow through the stove relies heavily on heat within the flue drawing the exhaust gases upwards. Inadequate flue temps mean less draft, less oxygen through the stove, less combustion, less heat, etc. I think having more than half of the flue outside would have a negative effect on flue temp, so I decided against that approach.
Knowing that I wanted to go straight up for optimal flow/maintenance, I needed to figure out a way to install/remove the flue as the roof raises and lowers. I couldn't find any double-wall flue options that weren't bell and spigot, which complicated things. I thought about fabricating my own flue with V-bands (which you see sometime on turbos/exhaust pipes), which would be easy to insert, but nixed that for time reasons. So I decided to find a way to just accommodate the bell and spigot connections on the flue that is made for the stove. For this, I attached the stove to a scissor lift table. After the roof is up, with the stove in the lowered position, I can insert the chimney into place, and raise then raise the stove to close the bell/spigot connections. It works pretty well! I can setup/breakdown in less than a minute.
IMG_20181201_173010359 by ben gibson, on Flickr
IMG_20190101_120336213 by ben gibson, on Flickr
Here are some of the other miscellaneous details, including the heat shield and roof connection. I made the heat shield out of some scrap aluminum 0.03" aluminum sheet I had, and it has worked well. Not much to say about it, other than it is spaced away from the walls in order to shed the heat.
The roof sheeting was too thin/flimsy to mount the deck fitting and exhaust cap, so I attached some 1/4" aluminum to the roof frame. It's pretty sturdy, which is nice for raising the scissor lift to get tight connections in the flue joints.
IMG_20181201_125915750 by ben gibson, on Flickr
IMG_20181201_131627087 by ben gibson, on Flickr
IMG_20190209_133803307 by ben gibson, on Flickr
20190426_102446 by ben gibson, on Flickr
20190610_215318 by ben gibson, on Flickr
20200725_002711 by ben gibson, on Flickr
Cheers!
