Is there a heating benefit to having a long vertical run (6 to 8') of single wall flue pipe in the living space (ie stove to ceiling) versus going through the wall as soon as practical? I'm thinking there's a lot of radiated heat to be gained.
Total vertical height stove to cap will be about 20'.
Thanks
Dave
You're not the only person that I know that's wondered THAT EXACT THING!
I can't answer that exact question but I've added the blowers that install in the pipe and the heat gain was impressive. Not sure of the make Heat-mor? Maybe
Sounds like you have the room for one might be worth looking into.
If you cool the hot gasses in that vertical run you can get back drafts and corrosive condensations.
If you make a 90° turn from vertical, that will heat up the wall of the pipe as the hot air contacts it to be forced around the corner. it will get very hot and be the first to rot through. our stove in the living room goes 16 feet straight up and through the ceiling and roof. that will give it the best draft. and we used double wall pipe to keep the temp up so the gas and water vapor do not condense on the walls of the flue. ( creosote ... flammable). you will get the most heat from the stove, and should not need it from the pipe.
On what Gary was mentioning, you will get more heat, however each setup and fuel is different. If you cool too much that is a problem. The heat extractors work well but are not recommended for that reason. This is the referenced standard;
NFPA 211: Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances (https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=211)
The more pipe you can have in the living space the better. Less chance youll light the wall at a short 90 too. Thimbles can only do so much.
If its just an old open chamber stove, baffling the block the flame from flying up the flu can about double heat in the burn box. Done it a few times. Have built a few stoves too. Only backdrafting ive ever had was from short lengths of flue in high winds. Add a stack section and it goes away.
I have about 6' of insulated where it passes through the roof and up. The vertical flue is about 25' total, the rest is single wall inside. I burn small, dry, with undamped air in a small stove and clean the pipe once a decade out of boredom. A very clean burn, most of the time after startup just heat waves out the stack. How you burn within each setup makes a tremendous difference.
Oh yeah.. A hot stack is maintenance free, i dont care what you burn in it. Ive run pure pine, pure vegetable oil, sawdust and waste vegetable oil, motor oil, you name it. 700f and up youll stay clean. I'd routinely get ripping and watch the sparks fly up into the night sky. The only brushing ever done (2x in 10 years) was just verifying that brushing was not needed.
I built one stove that is fed sawdust and wvo by an adjustable auger into a modified rocket with a swirl riser inside the main body. with secondary hot air injection along the riser axis and a 3 foot drop to reach the exit. In testing itll run 500avg on the body, 900-1200 in the 4" burn pipe and below 300 put the stack. Im anxious to put it into full time service and see if the stack temps cause any adversity. There is no ash to clean out and no smoke once its ripping so i dont think there will be a lot of unburned gasses.
A safety btw here. If you ever have a stove take off and the flue glowing in the basement DONT damper it down. Open the flue wide open and open the door wide open. Yes the flame will really get howling but the flue will draft tremendous volume of cool air. In a tight house youll need to crack a window or door because its huge CFM coming through. This cool air will cool the flue. If you want it to settle down faster keep a roll of toilet paper or paper towel near your laundry sink. Soak it and toss that in. The water converting to steam will rapidly suck heat out of that firebox and get it under control. As will misting it with a spray bottle. Just dont flood it with a bucket and crack a cast iron casting.
If you wanna fiddle with stoves sooner or later one will run away. Never load up one thats new to you and leave or go to bed until you are really in tune with its dynamics.
Thanks everyone for the tips and suggestions. I'm aware of the issue with cooling the pipe too much, that's why I asked.
If you decide to go through the wall use 2x 45 degree elbow instead of a 90 degree, less turbulence.
If you have a chimney fire , open a crack in the door and empty your fire extinguisher, the strong draft will pull it up inside the chimney
I went straight with double wall in the house because of code requirements. Check with your stove shop to see what they recommend for your installation and code enforcement officer when you apply for the permit. He will have the final say to get the certificate of compliance so your insurance will cover it.
I run a wood cook stove (Elmira Fireview), straight up stovepipe, single wall about 10', then 6' or so of insulated through the ceiling/attic. Dry wood, hot fires, rarely any soot. I clean it a few times a season just to be sure, never any more than a couple cups of dust.
Mike, you have such great advice, rhe toilet paper roll trick is one that would never occurred to me! Years ago We had a stove run away (Tamarack/larch wood, burns hot) and that advice would have helped! We ended up burning the paint off double wall pipe in that one.....
That's good to know about the cooling effects of those blowers . The ones I've helped put in were both in shop stoves that pretty much ran wide open heating quite a large space. Creosote wasn't an issue with either of them will certainly keep it in mind for the future though.
glad to help nathan. i havent had paint on a stove part in a long time. i have seen lava orange 3 foot up the single wall pipe a few times and thought for sure, its about to drip open and spew flame onto the floor joists above it.
ive spritzed water on sheetrock from a windex bottle to keep it from lighting while a runaway winds down, and watched it flash to steam. lots of excitement to be had when youre stupid!
Quote from: 21incher on September 06, 2021, 04:20:15 PM
I went straight with double wall in the house because of code requirements. Check with your stove shop to see what they recommend for your installation and code enforcement officer when you apply for the permit. He will have the final say to get the certificate of compliance so your insurance will cover it.
Good tip, I never thought to check with the township. Not exactly a metropolis here, we're lucky to actually have a township building.