Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: Mr. Maple on January 30, 2018, 02:05:17 PM
-
Okay,so now this furnace is really impressing me,we are into wood that's been under cover in the shed now for about 4 years,figured we should use it before it got too dry? Anyway,as stated before,first furnace would do an 8 hour burn on two wheelbarrow loads of wood,second furnace 6-7 hours on three wheelbarrow loads of wood,present furnace 12-14 hours on two wheelbarrow loads of wood,but now with the really dry stuff - ONE wheelbarrow load of wood for a 12-14 hour burn,sometimes even 15 hours!!!!
-
Got anything to do with outside temp, heating system changes, thermostat settings, different species of wood, etc do ya figure? Maybe your other wood pile was wet? I have a similar stove to yours on a smaller scale, and it makes almost no difference in mine when all other aspects are the same. 1 year old red oak at 25-28% MC lasts actually a bit longer than the trailer load of 5-10 year old red oak at 12-16% MC I brought home. Was stacked inside a hayshed for years until I grabbed it so it was super dry. Actually hated it
-
I have noticed with my p&m that if my wood is real dry like standing dead burn times go down the drain. If I throw in some dry with some wet or burn just spring cut wood burn times go up and can see my stove gassing into upper heat exchanger. I am not a scientist or good at science but I believe there needs to be a certain amount of moisture in the wood to support the burning of syn gasses. Great to hear your having success with the dry wood be interested to know mc %
-
If I remember correctly, Slim used to say he liked his wood closer to 30% then 20%.
I have found my burn times are longer if the moisture content is upper 20's to 30 percent or so rather than the wood that was less than 20 percent when I burnt it.
-
Dam wind and stuff ...messes wit me. I got every thing covered so u can't complain.. It was a bit better at my last place with out the trees...but I will suffer forth my view out my living room...
-
If I remember correctly, Slim used to say he liked his wood closer to 30% then 20%.
I have found my burn times are longer if the moisture content is upper 20's to 30 percent or so rather than the wood that was less than 20 percent when I burnt it.
Depends on the size as well, My wife fills the tote cages, if its the last one for the day and she’s getting tired the top half of the tote will be all smaller pieces. Give getting a thermocouple in the stack I notice a lot that small pieces lead to higher stack temps, my theory is they gas off faster and are drier being smaller which leads to higher stack temps.
-
You know If you burn dryer wood you need to slow down your draft like big time to get longer burns .
Im burning slabs that are 15-25 % I have the rain cap on and front fan intake 1/2 closed off and Im thinking closeing 1/2
of the back fan off .. if you don't all heats going out the chimney . stack temp monitoring is a big deal .
heat550
cherry red rain caps happen pretty easy . Mine has a nice blue color now.
-
Here like this.
Heat550
-
Not sure if I'm on the same page, but are "dry" wood burning woes solely attributed to excessive combustion heat going up the stack or poor combustion from chemistry? If the former, seems like a temperature controller and thermocouple in the stack would be a solution, then use a two speed blower or auxillary damper controlled via magnetic solenoid, or if you like to tinker use a 3 phase motor and motor drive with a PID controller for automated variable fan speed.
-
Your slowing down stack temp so heat goes in water instead of up chimney. Paint can lid cost .. .Free. more Electronics more problems.
:thumbup:
Name of the paint can lid.. combustion flow converter. :thumbup:
I could sell them on eBay and make millions.
Heat550
-
Cutting back the air only can help so much. At some point it will just be smoldering and blowing more smoke.
If the wood is super dry or you have a huge amount of surface area like with slabs, you want to limit the air coming up from under the coal bed and supply more air over the fire.
If the stove doesn't have any air in the top, you can just keep part of the grate completely uncovered so air can get to the top. Maybe even try to put wide flat slabs in first to block off more air from coming up from the bottom.
-
Cutting back the air only can help so much. At some point it will just be smoldering and blowing more smoke.
If the wood is super dry or you have a huge amount of surface area like with slabs, you want to limit the air coming up from under the coal bed and supply more air over the fire.
If the stove doesn't have any air in the top, you can just keep part of the grate completely uncovered so air can get to the top. Maybe even try to put wide flat slabs in first to block off more air from coming up from the bottom.
:post:
-
Thanks for info . My back fan is blowing down from the top. It's full open 150cfm fan under grate is 2/3 closed 50cfm it gets water dam hot fast.. with way lower stack temp.. I could tinker with it more.
Now that I know this.
Heat550
-
Here's what I'm doing to burn slabs I'm closing fan port about 2/3 of the way . Picture is Extreme setting to show how far flipper opens.
Heat550
-
I hear a lot about stack temps , how do you monitor that , I have a bl28-40 with 3 sections of insulated pipe,
-
I hear a lot about stack temps , how do you monitor that , I have a bl28-40 with 3 sections of insulated pipe,
I picked up a BBQ thermometer from Mills Fleet for $12 with a 4" probe. Drilled a hole at the bottom of the stack pipe and inserted the thermometer
-
This is a picture of the candy thermometer I installed. Drilled a hole in the stack and inserted the probe end.
-
Right now I just keep rain cap from glowing but I need to get a sensor on it . I'm thinking temp gauge on the back clean out plate would tell me enough for adjustment. I'm going to try oven temp gauge sitting on back clean out plate. :thumbup:
Heat550
-
Just to add . I tested some wet oak blocks in stove leaving it set to slabs drafting they don't burn they smolder. But they work good to keep a coal to start the slabs .. the drafting does work perfect . Set draft to moiture in wood . Just like old indoor stoves.. but saves you alot of wood that's for sure..
-
Old wood that has started to decompose has already lost some of its energy/calories/BTUs etc but until that point, the drier the better for me.....While "fresh" damp wood might burn longer, all it is doing is boiling off internal moisture...
-
Getting more tech in to the dry wood burning . Trick is backing off the drafts . Moiture meter took the mystery out of it . Now I want a remote temp sensor on chimney . And yes a Heatmor 400 can burn dry slabs . Takes chimney Cap and pans blocking off draft fans. Heatmor 400 1/3 full of dry oak slabs gets you 8 hours at -21f
Heating 6600sqft .. slabs burn super hot. 42,000 lbs of slabs for season central MN. That was my 2018 experiment.
Heat550
Heatmor 400 A.K.A Huge gasifier.
Picture of stove the draft fans are off. Can't have them on with door open . Cherry red rain cap is if you have pans on draft fans open to far.
-
thanks for sharing! I miss my 400!!! I only got to play with it for 2 winters before we moved!!
-
Heatmors have there place the old style there as versatile as the operator wants them to be. This is why I got hooked in to them.
I have no clue why my 2015 400 didn't come with draft covers.
I put marks where to set draft chokes for what ever moiture wood I'm burning . It saves alot of wood . And range is 40% to 10% it's ruffly 1/8 increments. If I would burn wet wood in a pinch. Remove rain cap and draft chokes. Maybe everyone knows this . But it's the reason Guys with heatmors like them . You can burn what ever wood you have ... Or dry wood and save the back. 👍😀
Heat550
-
yeap I agree!
-
Now I got some wood that 30-40 % oak I burning drafts wide open and rain cap off . Chunk wood takes alot of draft.
Heat550
-
Yup, makes a big difference.