Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: Scott7m on January 16, 2011, 06:41:32 PM
-
As some of you know I've played with burning a lump or two of coal every now and then just to see how it does. I finally called up a buddy who works at a coal dock and he said to come by and we'd load my truck down. I took my truck up and hand loaded it completely full of softball to footlball size lumps. I heaped it up and tried to place it to maximize my load. When I left my ball was probably 5-6" off the ground haha.
Sooo.. for the last 3-4 days I've been playing with the coal and will continue to experiment and let you guys in on what I'm doing.
I'm heating 22-2300 sq foot double wide in a Natures Comfort 175 furnace. The past several days have been typical winter weather, a lil warmer, but nothing crazy. Lows 10-15 Highs 25-30. Typically my burn times on seasoned hardwood can range from the shortest burns of 14 hour or so in zero weather to as much as 24 hours when the temps only bottom out in the high 20's. Since I started burning a bit of coal, I'll go out at night and throw in probably 20-30 pound of coal. Then add about 1/2 a load of wood over the coal, where as before I would cram it full. My burn times are now easily over 24 hours. I'll fill at 5 or 6 pm, go back out around 9 am open the door and smile. There will still be wood in there and those chunks of coal will be laying there glowing red. I'll usually just punch it around and wait for my evening fill.
This evening after a 24 hour burn I am sure that my stove would have went another 8-12 hours. I threw in about 20 pound of coal, and about 1/3 a load of wood. I'll update on how this done. Tonigt it is supposed to be about 10-12 degrees.
-
My grandfather told stories of heating his house with stolen coal. I suppose things haven't changed that much.
-
No, it's not like that. Employees of the coal docks are allowed a certain amount of coal per year. Some sell it, some use it, some give it away.
However, if you go into the coal fields where these haul rails run for miles in these vacant valleys you'll find coal theiving going on. They'll pry open the hopper door on a railroad car and the whole center of the load will fall out the sides. Then everyone and their brother comes along and loads up on it. Also, in extreme rural "poor" parts of eastern ky you'll see people and families digging coal out of the road benches where they've made highways.
-
I live in Illinois so we will be steelin coal soon!
-
Scott7m,
Glad to here you are experimenting too. My 1st coal purchased almost 1 month ago cost about $100 for 1000lbs. I'm still burning that load with wood and have given the smaller chunks to a neighbor who is hand firing a wood/coal stove. We both have experienced extended burn times. Looking forward to hear of your results!
Rick
-
Now that I've figured out and solved the problem with my OWB, I can go back to using a bit of coal again. Although recently I've been tossing in chunks of unsplit Bradford pear wood in sizes from 3" to 10" diameter. That stuff gives me about 18 hour burn times on one load. I can't imagine how long coal/Bradford pear would burn.
-
remember guys put the coal on top of your wood only, if you put the coal directly on the grartes you will crack or warp them, coal is very hot for a long period of time just something id throw out to ya
-
I burn coal directly on my grates without any issues. Heat Masters grates are easily replaced if I do have problems down the road.
-
I've got several customers burning straight coal. Not
heard a problem yet.
They sell coal here for $120 a ton, I heard another place sells it for $90 but
it's further away.
-
I finally have my one ton dump truck on the road and I'm heading out this morning for a load of coal. I hope to buy enough to finish the year and most of next as well. Also I'm not going to have to unload it by hand when I get home!
-
I wish we could still get coal in Iowa. :(
-
Other than coal getting very hot, are there any other risks of burning coal in an OWB? I have a WM 4400 that is all boiler plate, what are the risks.
-
My 325G does not have grates; there are fire bricks spaced out along the bottom. I let the boiler burn down to embers before adding coal. I rake the embers out evenly on the bottom; place 2 6to8 inch green rounds on each side then shovel in the coal in the middle on top of the wood embers. Two scoop shovels is plenty, then fill with wood. At mid 20 highs and mid teen lows I can leave for 36 hours and come home to a warm house (thermostat at 60) 36 hours later. At 70 I can make 24 to 30 hours before needing to reload.
-
Other than coal getting very hot, are there any other risks of burning coal in an OWB? I have a WM 4400 that is all boiler plate, what are the risks.
I've yet to see burning coal be a problem in a boiler surrounded by water. Natures Comfort boilers have water completely surrounding the jacket, even on the front. The only time I can see it being a problem is that if you had a boiler that had no water perhaps in the back or front, and you had coal laying against it. However, if you keep your coal where it should be there is little chane for problems as there is water just basically on the other side of the metal. I don't know if any of you have ever experimented but you can take a cutting torch and you can't even burn a paper cup if it has water inside of it. Now on old time wood stoves and outdoor furnaces that use air, you do run the risk of warping or distorting your stove. There is no water surrounding the firebox and that allows the temps of the firebox metal to skyrocket.
I always have a good bed of coals/ashes and never worry about it warping my grates. Heat wants to rise.. I'm not saying that it CANT warp your grates. But with a little care and precaution I don't think you would ever do it.
My coal experiment is doing very well. I've been cutting my wood fill back more and more. I've basically putting in 20-30 pounds of coal each night, and I've cut my wood back to probably 1/3 of what I was burnign a few weeks ago. I am getting solid 24 hour burns and when i go to fill the stove at night, it still has a huge bed of coals and the temp is still at 158.
-
On another Coal experiment note:
I've got a customer burning coal in an NCB-250. He's heating a 2800 sq foot house, a 2 story garage that measures out probably in the range of 2200 sq ft. He's keepin the garage at 60 and his home on 73. He's had the temp of his OWB set at 160 all season. We checked the temps out of his register in the house and it was 122. I said that was over-kill. We dropped the temp on the stove back to 145, temp out of the register is now 110-112, coal use is now now probably 1/3 of what it previously was.
-
Updating again.
Temps yesterday at the time of fill up were around 25 degrees. They fell through the night into the 8-10 degree range. Today we had a high of 17.
Last night at 4pm I put in a descent chunk of coal, probably 30 pound. There was already a lot of coals in the stove, more than I need to have. Burning coal seems to make more coals.
It heated my home for 30 hours. I went out tonight at 10pm and the stove was down to 140. It's usually at 158. I opened the door to a huge bed of glowing coals but the temperature at 10 was already down to 4 degrees. So we're heading to 0 tonight.
Natues comfort has an adjustable slider on the fan. I usually keep it set pretty tight because I have seasoned wood and dont' really need that much air. Sooooooo... Tonight I decided to open up my fan almost all the way to give it probably twice as much air. I'm doing this hoping it will burn up more coals. I also have to say that I haven't really done much to the stove the past week, i've hardlly stirred up the ashes at all, and have just been refilling. I can't complain though when it's going over 24 hours per fil in single digit weather.
The weather man said we should bottom out in the morning between 5 and 10 above. Boy is he wrong, he said it would be cloudy all night.. There isnt a cloud in the sky and the moon is lighting it up like daylight :) By 10pm it was already 4 degrees! I suspect in the morning we will be somewhere in the -5 range.
-
I also want to add that burning coal is a lot different than burning wood. Wood has a certain way or stove set up that it operates it's best at. I had found that level when I was burning straight wood. As far as burning wood and coal together, I am in the beginning stages of optimizing the stoves performance.
My stove doesn't smoke very much anyway, but through the day with that glowing bed of coals left over. You never see smoke. Thats something else thats nice, but when you first add coal and its burning the first burn. You get quite a bit of yellow smoke.
-
Ok.. so last night I had commented I let my stove get down to 140 and it was still like 4 degrees outside.
I noticed last night my fan was running nearly non stop in the house. I went out to check the stove and it had a lazy fire and the water temp had dropped to 90. I couldnt figure it out with the fan being on high. Sooo.. I'd punch the fire and wait and look inside still lazy, and i'd notice the fire would flare up when I opened the door. So I slid my ash pan out and stuck my hoe up in the slots between the brich and some powder was packed in there because i let my ash bed get to deep, because I've not been raking it down like I should.
Sooo.. last night middle of the night it was 2 below zero, stove was down to like 80 and when i put my ash pan back in and opened the door i had a ROARING FIRE! sooo. i went back inside .. house was set on 73 and it was 71. looked outside 20 minutes later and there was sparks rolling out my chimney from my previous adustment. I went out and put it back in the original spot I had it in and shut the door. Waited a few minutes and checked the fire, still roaring.
This morning I went back out at 10 to check on it.. stove was up to temp and operating as normal. Looks like there is plenty enough wood/coal to take me on for another 12 hours.
-
Glade to hear that you are getting such long burn times with your NCB-175. I only wish mine would do the same. I have tried everything besides buying a different OWB and can’t get no more than 20 hours burning coal and wood. And that’s when I’m home to stir the coal bed occasionally and with temps dropping to 18 at night and highs back to mid 30’s. Single digit temps burn times are much shorter.
I have tried all dry wood, some green and dry mix, large pieces small pieces, wood and coal mix loading with all large wood filling in voids with small pieces, loading with all small you name it I have tried it. Tried reducing load and not heating basement so I am only heating 1850sq. ft. The only thing that has made very much difference in burn times is adding coal. Which puts off a real bad odor when first loaded.
I have tried more air into firebox, less air, found less air is better, more air burns more wood.
Burning just wood single digits at night, I do good to get 10-12 hours with a full load of hardwood, all you can possibly put in and close the door. I usually have to go out after 10 hours or so and move the wood that has not dropped down to over fire grate.
Using smaller pieces only, seems to produce shorter burn time. So I try to load with as many large rounds as I can then fill in the voids with smaller pieces.
I have my stove set at 145 on, off at 155. Raising water temp more only increases wood consumption.
So hold on to that stove it is doing you a fantastic job!!! :thumbup:
-
Scott7m Do you have shaker grates in your setup?
I've had mt NCB-175 up and running since the 1st of Jan. and am getting 12-14 hour burn times easily. I would like to experiment with coal also. I'm in PA so anthracite coal is readily available and fairly inexpensive. A 24 hour burn time sounds nice! :thumbup: