Wood stove pipe size VS draft

[gsganzer]

I have access to all the dry standing oak I want. It's typically been dead at least 2-3 years if not more. It just depends whether it starts to get termites in it, which will kill a saw chain in short order. Anyway, I try to cut and split it now during the cooler months, but it will be used next year. Once it's split it dries pretty quickly, you could probably cut and split in the summer and it would be dry by the fall. But who in their right mind wants to be cutting firewood in the middle of a TX summer (never mind the fire hazard).

 

[NYlumberman]

Flu temperature is important! It’s a Goldilocks like conundrum. Too cold and the VOCs volatilized from the wood condense in the chimney. Too hot and you can damage the chimney, and maybe burn the structure.
I heated my home, an old farmhouse, for 35 years, exclusively with wood. I also was responsible for the wood fired boilers that heated our dry kilns. What I learned is that wood combustion is chemical reaction that occurs in two stages. The first begins at 451 degrees and combines one oxygen molecule with one carbon molecule, that reaction results in CO and releases about 30% of the potential energy (BTUs). The second reaction occurs at 1200 degrees when a second oxygen molecule is added to form CO2, that second reaction releases 70% of the BTUs.
When you turn down a big stove so the furnace temperature is below 1200 you have incomplete combustion (think smoke).
When you look at a fire, the coals are carbon, the flame is the VOCs igniting.
Water is a byproduct of combustion. The water vapor in flu gas will be the moisture in the wood being flashed off plus the water produced by combustion. Creosote is condensed VOCs and has plenty of carbon available to burn. So ideal flu temp is between 212 and 450 degrees.
All cellulose has 8000 BTU/Lb. bone dry. Most dense Hardwood have 50% moisture green and that reduces the BTUs to 4000 BTU/Lb.
Almost impossible for your stove, fuel and ambient temperatures to be ideal all the time. My solution was two stoves, a big one in the basement and small one in the kitchen both hooked to an insulated masonry chimney with two 8’ flus (laid up with regular cinder blocks and the gap filled with vermiculite).
At 77 I got lazy, and my honey hated it when I went up the ladder to clean the chimney. Upon review…brevity is not my strong suit.

 

[bvanek]

I have to agree that the 6 inch flue drafts better and heats up faster.... and when you get to the top where most creosote is formed (cooler) then it then becomes more of a stove-flue relationship. I have never had creosote build up in the stove itself, so I can't comment on that.

So for me, its a three part system; a manual flue damper, air intake adjustment, and a guy who monitors and feeds the stove(me). My stove has a pretty decent design internally as the air tubes are located at the top....this creates better combustion, maybe some will say re-burn just before it enters the flu...(hotter). Then it depends on whether you leave the stove un-monitored like at night or while away....or if you are around and can make adjustments periodically.

I work the damper and air together and also load the stove with different sizes and types of wood...Fir burns hotter and faster, hardwood slower but leaves more ash.
I am retired so during the colder weather I become the thermostat for the most part. But I can also adjust for allowing to burn through the night as well. The stove design for sure is a factor..but everyone has their own unique system and wood sources so it's not always one size fits all.

Seasoned wood, YUP! at least one year ahead, but depends on the wood, when you cut, and also the typical weather pattern in your area.

 

[dodge man]

I cleaned my flue this last fall and got almost nothing out of it, just light dust. The last time I did it, maybe 5 years earlier I got enough to maybe fill a 5 gallon bucket and inch deep. It was a very dry material like coarse sand. I’m not sure what creosote even looks like??

 

[Rockbadchild]

I cleaned my flue this last fall and got almost nothing out of it, just light dust. The last time I did it, maybe 5 years earlier I got enough to maybe fill a 5 gallon bucket and inch deep. It was a very dry material like coarse sand. I’m not sure what creosote even looks like??

Rhetorical question ??

Its the same for my house almost no need to clean the chimney but I have a hunting camp that produce a ton of creosote, also my garage create some... It is a lot worse for stove that don't runs constantly or runs constantly chocked ... before someone ask the hunting camp wood is 10 to 20 years old and stored in a outdoor shed and we choked it because if not it gets way too hot and there isn't enough window to open.

 

[dodge man]

No I really don’t know what creosote looks like. I’m using a fireplace with an outside air intake. I’m not sure how long my flue is. Maybe 15 feet or a little less.

 

[Rockbadchild]

No I really don’t know what creosote looks like. I’m using a fireplace with an outside air intake. I’m not sure how long my flue is. Maybe 15 feet or a little less.

its a black tar that can become liquid when hot

 

[dodge man]

I’ve got a friend with a wood stove in his basement and I’ve seen the liquid stuff on the outside of his chimney on the roof.

 

[BnRidge]

As a beekeeper with a smoker I got to see what creostote looked like. Fuel was smoldering pellets like what's used in pellet stoves. Nice and dry, yet with black goo oozing out the lid and down the sides. And if I got a nice bunch of coals inside and pumped it good and hard, it would light off just like a chimney fire, crackling and sizzling down the sides. That was one way to clean it. Just like my neighbor - run his stove low and smoldering all fall, then on the first real cold morning fire it up extra hot and it goes off like a roman candle.

 

[drumminj]

As a beekeeper with a smoker I got to see what creostote looked like. Fuel was smoldering pellets like what's used in pellet stoves. Nice and dry, yet with black goo oozing out the lid and down the sides. And if I got a nice bunch of coals inside and pumped it good and hard, it would light off just like a chimney fire, crackling and sizzling down the sides. That was one way to clean it. Just like my neighbor - run his stove low and smoldering all fall, then on the first real cold morning fire it up extra hot and it goes off like a roman candle.

Agree that a smoker is a great way to visualize creosote. I use a propane torch to 'cook' it off, but it's crazy how quickly it builds up when you're purposefully burning low and slow.