Trying to burn nut coal and have questions....

Trying to burn nut coal and have questions....

PostBy: Str8liner On: Fri Jan 09, 2009 7:07 pm

Hi all, I have been lurking in the forums for a few weeks and wish I had found this site along time ago. For years, I had a Keystoker in my garage and burnt rice coal but this past fall I found out the heat exchanger was all rusted up. So, I got a good deal on a Brunco 190 hand feed furnace that will burn wood or coal..
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I installed it last weekend and decided to try and burn hard nut in it. Its been up and running ever since I first lit it, But its air tight with the exception of the adjustable vent thats on the draft blower. The blower is hooked up to a 110V thermostat but if I let the thermostat try to kick on and off and regulate the heat, the garage cools and then the blower runs and runs and runs trying to bring the temp back up.
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The problem I run into is that for me to keep the nut coal burning right and keep a nice hot steady fire I have to keep the ash door cracked open about 3/8" so it gets enough air. If I close it it will just cool down to the point it doesn't put out enough heat. I called Brunco and talked to them today and he said I should switch to soft coal because the firebox is too big to burn hard coal effectively....???? The fire box is 30" X 18" and about 10" deep. Is that to big to burn hard coal in? I hooked up a Dwyer manometer to it today and with the fire burning like I want it and the baro adjusted I get a solid .05 draft. But if I close the ash door the draft drops to .02-.03 or so and the fire will slowly cool. I am considering drilling a hole in the ash door to add combustion air and I wanted some opinions on this, and weather or not I should try the soft coal.

Also if I add the extra draft on the ash door does anyone know of any electric controlled draft kits or something that I could tie into my thermostat? Thanks for any advice or help in advance!!!!!

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Str8liner
 
Stove/Furnace Make: Brunco 190 Keystoker 250
Stove/Furnace Model: Keystoker 250

Re: Trying to burn nut coal and have questions....

PostBy: gerard On: Fri Jan 09, 2009 7:20 pm

I don't buy that the box is too big to burn nut, it looks about the same size as mine, maybe even a little smaller. I DO have a manualy adjustable damper in addition to a thermostatically controlled one. If I close the manual one totally the fire will burn out unless it's really cold and the electric damper opens regularly. Sounds like the problem you have would be adressed by being able to add some vent air to keep a minimal burn. Looks like you may be able to drill a series of holes in the ash door?? Not sure why they would design something without a manual draft - just lets you tweak it a little better......
gerard
 
Stove/Furnace Make: yukon dual fuel
Stove/Furnace Model: husky

Re: Trying to burn nut coal and have questions....

PostBy: gerard On: Fri Jan 09, 2009 7:21 pm

PS - looks like you also need to add more coal to the top of the bricks :D
gerard
 
Stove/Furnace Make: yukon dual fuel
Stove/Furnace Model: husky

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Re: Trying to burn nut coal and have questions....

PostBy: Str8liner On: Fri Jan 09, 2009 9:14 pm

I have had it heaped up above the fire bricks and with the ash door cracked open that baby burns like a smelter at Bethlehem steel. Sadly when you close the ash door up tight it slowly withers down to where its barely making enough heat.

The garage I am trying to heat isn't insulated real great and its a bit drafty so I need to keep a nice hot fire and a steady supply of heat on colder days like this.....
Str8liner
 
Stove/Furnace Make: Brunco 190 Keystoker 250
Stove/Furnace Model: Keystoker 250

Re: Trying to burn nut coal and have questions....

PostBy: Dann757 On: Fri Jan 09, 2009 9:23 pm

I think you should put a spinner air inlet on the ash door, you could adjust it or close it off completely. Is that a spinner on the fire door? You could order one and figure out how to work it in!
Dann757
 

Re: Trying to burn nut coal and have questions....

PostBy: grizzly2 On: Fri Jan 09, 2009 9:56 pm

Str8liner, I think gerard and dann have given you the correct answers to your draft problem. Good luck. :)
grizzly2
 
Hand Fed Coal Stove: Hitzer 30 - 95
Coal Size/Type: pea and nut/ anthracite
Other Heating: Jotul #3 wood stove in garage. Oil backup in house. Electric backup in house.

Re: Trying to burn nut coal and have questions....

PostBy: Str8liner On: Sat Jan 10, 2009 1:10 am

Is that a spinner on the fire door?


Yep it has a spinner on the loading door for draft over the fire.

Should I have it open or closed when burning hard coal? I would think with the draft problem I would want it closed but when I have a large fire going it seems to like it open some. I think its open 1 turn right now. Maybe a big fire likes the oxygen or something.

This stove also has a heat baffle in the top you can pull in and out but it doesn't seem to effect my draft situation much....

I am going to pull the ash door off tomorrow and try and fabricate something up. Will post some pics of what I come up with....
Str8liner
 
Stove/Furnace Make: Brunco 190 Keystoker 250
Stove/Furnace Model: Keystoker 250

Re: Trying to burn nut coal and have questions....

PostBy: ssettle On: Sat Jan 10, 2009 11:08 am

I have the same brand of furnace but mine is a 120. I have mine in the basement of my small ranch house. burns nut coal just fine, most of the time it's 74 degrees in my living room. Heats my place better than my oil furnace did. My place does cool down somewhat on windy days but it could be insulated better,plus I'm also heating a large room in the basement. I hooked a up the cold air return to that was on the oil furnace which seems to help. I thought about drilling small holes in my ash pan door to better control the fire so it would burn hotter but decided to hold off till I get this coal burning thing under better control . I learning as I go along and getting better at it. This forum has been a great deal of help, you can learn a lot here. Good luck and keep us posted.
ssettle
 
Stove/Furnace Model: none

Re: Trying to burn nut coal and have questions....

PostBy: DOUG On: Sat Jan 10, 2009 1:41 pm

Str8liner:
I started out with a Brunco 190 furnace and tried burning that beast with wood, bituminous lump coal, anthracite in stove and nut size. My neighbor bought a Brunco 120 at the same time and is still using it, but only burns wood in it. He could not get his to burn coal either. From my experience with the Brunco 190 and observing my neighbor's Brunco 120, the only good thing I can say is they are probably the best constructed and welded furnace out there. The design though, was definitely for burning wood. It doesn't burn coal well at all. Bituminous is possible, but hungry, anthracite without control and will not keep burning, because the design has serious drafting issues for burning coal.
If you are going to keep that beast, I would definitely drill the ash door for a spinner or two. This will change the whole burn characteristic and actually allow you to burn coal in it. Back then, I wished someone would have confirmed that idea when I still had the stove. The guys at Brunco kept telling me it would void the warranty, it wasn't tested that way, we don't know if it will work, it was my chimney, my coal, the way I was firing it. So, I got so frustrated with Brunco, I sold the furnace and bought a Clayton 1600. If it wasn't for the guys at Brunco, I would have never found a more superior and efficient operating furnace. They deserve the credit for making me shop the competitors.

Back to the Brunco, I found when I attempted to burn coal, flyash would build up very fast in the V-shaped secondary baffle plate, almost closing off the flue outlet. Keep an eye on this area. I didn't and let the ash build up. Then kept the ash door open in order to keep the fire burning. Eventually over firing the unit and warping the steel baffle plate. I wanted to run a domestic hot water coil in it and found the back of the stove had two 1/4" plates spaced about an inch or so, making it impossible for me to drill through it, that close to the flue outlet.

Other than drill the holes for a ash door spinner, I would consider insulating the red heat jacket. Boy will you notice an increase in the heat transfer efficiency into the duct work.

So, once you correct the deficiencies in their design, you'll have a pretty good reliable, almost indestructible, high heat producing monster of a furnace. Keep us posted on you decision and progress. Hope this helps, :idea: :) DOUG
DOUG
 
Stove/Furnace Make: CHUBBY, D.S.MACHINE BOILER
Stove/Furnace Model: CLAYTON 1600

Re: Trying to burn nut coal and have questions....

PostBy: gerard On: Sun Jan 11, 2009 8:23 pm

I should have looked at the pic closer. Your set up looks similar to mine. I also have a spinner in about the same place as yours (mine is actually above the loading door) and I initially had it all the way closed and had the same problem you describe. Once I opened it a little it keep the fire going and I haven't lost one since. Open her up - when you start overheating back it off a little until you find the sweet spot. Sounds like you're choking your fire off with a lack of O2 and the spinner should solve that. Let us know how you make out.
gerard
 
Stove/Furnace Make: yukon dual fuel
Stove/Furnace Model: husky

Re: Trying to burn nut coal and have questions....

PostBy: Str8liner On: Tue Jan 13, 2009 2:39 am

Well, I got around to "modifying" the ash pan door and it made quite a difference in my fire control. I ground the ash pan warning letters off and drilled a 2 1/4 inch hole in the center, then made a tear dropped shape cover that swivels over the hole. Will try to post some pics of it tomorrow if I can.

Doug, is the "V shaped baffle plate you are referring to the one that slides back and forth up on top?

Gerard, I found that mine needs the draft on the loading door open at least 2-2 1/2 turns when I fire it hard during these cold days.....At night when I bank it down I close it off to mabe 3/4-1 turn or so.....

Thanks for the replies!
Str8liner
 
Stove/Furnace Make: Brunco 190 Keystoker 250
Stove/Furnace Model: Keystoker 250

Re: Trying to burn nut coal and have questions....

PostBy: DOUG On: Tue Jan 13, 2009 6:54 am

Yes, the V shaped baffle plate is the one that slides back and forth. The purpose of that plate is to keep the smoke longer in the stove by creating a longer path for it to travel through. Thus, making what they call a secondary combustion chamber for the gases to be ignited from the feed door spinner. The tear drop cover that swivels over the hole is something I had not thought about but it sounds like a good idea. I thought you were going to buy another spinner like the feed door and put it in the ash door. I'm just wondering whether you still have enough air entering through you new modification to obtain the best results fraom your Brunco 190.

To obtain complete combustion of a pound of coal, 200 cubic feet of air are needed. The rate of combustion is controlled by the amount of air that is supplied to the fire. The more air from under the fire when burning coal, the faster rate of burn and the more heat that is generated. The answer to why a furnace is not supplying enough heat is that the drafts are not open enough or large enough. The rate of burn is also governed by the size of the fuel and the draft created by the chimney the furnace is connected to. On the other hand, excess air tends to cool the fire and takes more heat with it up the chimney. This balance changes as the fire goes through different stages of the burn cycle. Anthracite nut coal burns about 8lbs. of fuel per square foot of grate area per hour. So if you take the grate square foot area X 65%burn X 8lbs of nut X 12,500btu for coal, this will give you an idea of the heat btu per hour.
Example: I think your Brunco's grate is 15" x 35" = 450sq.in. / 12 / 12 = 3.125sq.ft. X .65 x 8 x 12,500 = 203,125 btu's per hour. Pretty close to their conservative advertised output at 190btu's.

So, when first starting or recharging the fire, the feed door spinner needs to be open to burn off the gases. After the charge is ignited, all the air should come from the ash door opening. If it is not large enough to give the required air, either make it larger or increase the draft through the fire by increasing the draft above .06 inches in the chimney. If the chimney can't create anymore draft on it's own, either induce air through the fire with a larger opening in the ash door or use a draft inducer fan in the chimney. So you can see that the best we can hope for is an average efficiency that is as high as possible.

Just something to play with and think about. Hope this helps. I'm looking forward to seeing pictures of your modification. I know your Brunco 190 will now be a mean heating machine! :idea: :) DOUG
DOUG
 
Stove/Furnace Make: CHUBBY, D.S.MACHINE BOILER
Stove/Furnace Model: CLAYTON 1600

Re: Trying to burn nut coal and have questions....

PostBy: CapeCoaler On: Tue Jan 13, 2009 9:28 am

For your caculations
Example: I think your Brunco's grate is 15" x 35" = 450sq.in. / 12 / 12 = 3.125sq.ft. X .65 x 8 x 12,500 = 203,125 btu's per hour. Pretty close to their conservative advertised output at 190btu's.

What do the ".65" and "8" stand for?
CapeCoaler
 
Stoker Coal Boiler: want AA130
Hand Fed Coal Stove: DS Machine BS#4, Harman MKII, Hitzer 503,...
Coal Size/Type: Pea/Nut/Stove

Re: Trying to burn nut coal and have questions....

PostBy: DOUG On: Tue Jan 13, 2009 6:25 pm

.65 or 65 % is the efficiency of the burning of the solid fuel in the furnace. Gas furnaces can be 70 to 90 + % efficient and electric the say 100%. The 8 is the amount of nut coal that can be burned in one square foot of grate area per hour. If you are burning pea coal, it would be 5lbs per sq.ft. of grate per hour. Bituminous lump coal would be 9.5lbs and wood 20lbs per sq.ft. per hour.
DOUG
 
Stove/Furnace Make: CHUBBY, D.S.MACHINE BOILER
Stove/Furnace Model: CLAYTON 1600

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