Anthracite Coal

[laynes69]

I'm currently burning good hard coal. It burned last night okay, but I am having issues getting the coal to its maximum burn. It has not even came close to glowing orange on the top any time of any fires. If I open the ash pan door the coal increases in temps, and my furnace throws more heat. I have no overhead air, and I have nothing but air coming in under the fire. I have closed my barometric damper but still won't draw well. I know the chimney is clean, and I wondered if the main loading door gasket was leaking and the flue had a few leaks, Would this cause what I'm experiencing? My ash pan damper is open 6 turns, with a gap or 3/8 if an inch. The fire hasn't gone out, and I am faithful for shaking, but I need more heat. Currently my furnace has close to 100 pounds of coal in it, this should pump out the heat.

 

[mtarbert]

Is the Coal dry? Maybe 100lbs is too much ...try 50-75lbs

 

[Corie]

With the ash pan damper open that far you should have a ROARING fire going. My stove takes less than 1 turn to produce a lot of heat. If you suspect leaking gaskets, fix them, although I watching a Russo run with very leaky loading door and window gaskets and display no symptoms of poor burning or low heat output.

How are you starting the coal? Are you allowing the chimney and furnace to get quite hot before adding the coal? How strong is the draft generally? Does it look like air can get to the coal bed through the ash pan door damper and the grates?

At all but the lowest burn levels, coal generally should show visable orange, if not on the very top layer, at least somewhere down in the coal bed. You should see those blue flames for a good chunk of the start of the burn as well.

It doesn't sound like you're getting very good airflow through the grates though. Inferior grate design perhaps?

 

[ansehnlich1]

Sounds like a draft problem. Coal will sit and smolder unless it gets good air, though too much air, and left unattended and you can have a seriously hot fire!

Gotta shake it down good, might have too much coal ash in there on the bottom and no air can get in.

Maybe some big clinkers laying in there on the bottom too, should be able to feel 'em catch when you rock the shaker arm.

I'd sit next to it, open the draft way up, get a cup of coffee, or whatever your beverage of choice is, and wait for it to get up to temp. It ain't wood you know, a low burn/smoldering coal bed might take a half hour or more of open draft to get going, you should be able to get that coal a bright orange glowing in there, looking like a blast furnace, and blue/yellow flames bouncing off the top of the coal bed when it's going good.

 

[laynes69]

Draft isn't an issue. I sealed all of the flue pipe, and seemed to help a little. Its 27 degrees and I can't get the house over 70-71 with the furnace. The coal is burning well I guess, its a bright orange just below the surface. It gotta be the furnace. I've had it burning for 2 days now, putting off even heat, but not enough. I have ran 150 to 160 pounds of coal through it since 6:30 last night, which included the inital load. I had a good bed of hardcoals, and the chimney is known to overdraft. I opened the barometric damper a little and that helped. One thing I am wondering is on the front cast iron liner in the firebox, there are 2 oval slots about 1/4 x 2 inches on the top. They come from the ash door up into the firebox. I am thinking that those holes are robbing some air from under the firebox. It has good grates, which shake down well, and there is air going down through the whole grates. Like I said though with that amount of coal, the air coming from the registers should be greater than 90 to 100 degrees. With good secondary combustion on wood, I can produce a hell of alot more heat in the home. There are no clinkers whatsoever, and I have shaken down the coal so I could get more air to them.

 

[ansehnlich1]

i burned coal for 7 or 8 years in a little baker coal stove and heated my 1200 sq. ft. rancher easily.....i used to say "how hot do you want it?"

the thing i'm not getting and havn't heard from you is you ain't telling me you're seeing flames. my coal stove when fired up would throw flames up like a roaring wood fire. it still sounds like that coal bed is starving for air, open 'er up 'til you see some flames, just stay close to it until you know how/where to set you damper and draft....

open 'er up too far and walk away from it and you might come back to a blast furnace....

 

[laynes69]

I've had blue flames above the fire when I reloaded, about 3 to 4 inches high. I have my ash pan damper set all of the way open, I can't give it no more air without opening the door. What I will do is open the door and keep it open and observe it. I just don't want to overfire the furnace. I see flames till the gases die down some. One thing I forgot to add is I have it tied into the ductwork in series. When the air around the firebox hits 140 the main furnace blower kicks on blows the air around the firebox and into the ductwork. This air is around 65 to 70 degrees. But the thing I don't understand is wood even with a tiny little fire in the back of the firebox puts out more and hotter heat than the coal. So I will try barely cracking the door and seeing what happens.

 

[ansehnlich1]

ok, those blue flames you see right after loading are from the coal gasses burning off, but you should be able to open up the draft enough that the coal will burn and produce a steady flame, that orange glow will get brighter and brighter 'til you see the flame start to rise up. it can be tricky, but i had mine down that i knew exactly how many turns my damper knobs would come open to give me an exact temp. on the stove thermometer.

a couple other things i'm thinking of, if your house is real tight maybe open a window or something and see if that don't get 'er going some more.

i looked your unit up on line, that bad boy should make it feel like maui in there, you oughtta be able to run around nekkid all winter long.

p.s....you gotta keep an eye on that thing til you get er down to a science, i don't want you overfirin' it either. one thing for sure, coal and wood don't burn the same

 

[laynes69]

The coal bed is so large that I really think it needs a ton of air to burn properly. Every time I tried contacting them about the anthracite coal they couldn't help me. Well thats because they burn soft coal in them. I really don't think that they were designed to burn hard coal, but the shaker grates, the firebricks and all castings are made for the heat. I have the ashpan door cracked a little and something there to keep it from going any farther. Well the coal bed now is looking like a real coal bed. It has that nice bright glow and some flames to boot. The house is coming up in temp and its throwing some heat out now. My coal bed is about 12 inches wide at its base, 22 inches wide at the top and from front to back its around 28 inches long. Also is about 10 to 12 inches deep. If it stays this way, I will keep it here.

 

[ansehnlich1]

Hey I just read your latest post. You see, that bad boy will put out the heat, that coal bed was just not firing likely due to lack of air. I'd try to go with what was stated earlier, a smaller pile of coal in there. You'll have to experiment with it til you get it down. Maybe once you get it burning like you stated in your last post here, you could close up that ash door and it would be ok just with that draft adjustment knob.

 

[ansehnlich1]

one more thing, try to build your coal bed more deeper and narrower, that's better than less deep and wider. I mean, shooting for a pile of coal 12 or 15 inches wide and 2 feet high is better for burnin' than 2 feet wide and a foot high. if that don't make sense let me know and i'll try and explain better.

 

[Michael6268]

If you havent done so already, hope over to the coal forum @ www.nepadigital.com . There is currently a lot of discussions going on about that stove. It doesnt appear to be a good anthracite burner. Think they all burn bituminous.

 

[webbie]

Another thing to consider - the exact amount of air that you blow over a heat exchanger is VERY important. If you blow too much air over it, it acts as an insulator and can actually hold heat in. Too little air can also cause a problem.

And, btw, no roaring fire with hard coal....the blues flames are all you should see. Hard coal is mostly pure carbon which does not have flames.

Yes, that much coal should put some heat out. We have no way of knowing the heat load of your house, but each pound of coal should put about 10,000 BTU into the home. So you are running at about 8 lbs per hour or 80,000 BTU+.

My newer 2700 Sf house in Ma. uses about 25,000 BTU an hour in this cold weather. Of course, a large drafty house could need 100K+

 

[ansehnlich1]

[quote

And, btw, no roaring fire with hard coal....the blues flames are all you should see. Hard coal is mostly pure carbon which does not have flames.

quote]

I'm not into a big argument here, and don't want to step on any toes, but I burned Reading Anthracite for 7 years or so, nut coal, and with my stove when the draft was opened up she'd rip a big burn for sure, bright orange flames atop a bed of bright orange coal, but when banked down I'd have those lapping blue flames.

I'd also have a fine black dust over everything in the house......it's wood for me from here on out.

 

[webbie]

"Anthracite ignites with difficulty and burns with a short, blue, and smokeless flame."

Anthracite contains from 92 to 98% fixed carbon. Which means only a tiny bit of % left to contain gases.

I can't dispute what your coal did, but having seen, installed and burned 100's of anthracite stoves it has been my experience that flames are as described above - short and blue. Your yellow or orange flames, in my opinion, are due to either lower carbon content (and higher volatile) coal or to excess dust which is being sucked up and ignited above the coal bed.

In the case of this thread, I think it could be very misleading for the furnace user to think that he should have flames. Even if he did, that is still not where the heat lies, as the real heat from coal is from the glowing bed.

Anthracite: "A dense, shiny coal that has a high carbon content and little volatile matter and burns with a clean flame. "

 

[laynes69]

Well I know I may get some crap here, but I modified the wood furnace. My forced draft was above and in the back of the firebox so it wouldn't work to well with coal or wood. So I mounted the draft fan on the ashpan door. I have it set on a thermostat, with a limit also so it can't get too hot. I am able to control the draft it puts out by a damper and I also put a piece of steel over the rear hole where it used to be so if I burn wood, I get this for secondary combustion. I have only a few inches of coal because im gonna let it burn out and burn wood, but its 32 degrees here and I have the thermostat on the forced draft set for 75 and it drops down to 74, forced draft kicks on, the the blower kicks on. At 75 the forced draft blower kicks off and the fire dies down and the furnace blower kicks off. Its working well, almost like a gas furnace. I did it because I can regulate the draft from all areas of the furnace. If the power would die, I can draft down the furnace for a low burn.

 

[webbie]

Yeah, you will probably get some crap - including some from me!
I know folks who did mods like this - his wife was sent to the hospital when he almost poisoned the family to death.

I think you are playing with fire.....not wanting to debate it, but if you really want to burn coal, you should buy something that is designed properly for it. Until then, buy at least two extra CO detectors and some more smoke detectors.

 

[laynes69]

I have a fire extinguisher in the basement. We have 2 co detectors, and we have multiple smoke alarms in the home. The bigger model has the forced draft like this, along with a firebrick baffle. We have a masonary chimney thats 35 feet high. The damper on the forced draft is open not even a quarter of an inch. Just enough to keep draft when the unit shuts down, and to help feed the fire a little. Its something for me to try and is 100% reversible. The only other option was making another draft knob so I could give the firebox more draft. When the fan shuts off, the fire goes back to normal. It will burn this coal just fine, the problem was I need more air.

 

[elkimmeg]

Don't play with me because you are playing with fire.

shaking my head whow!! you are re engineering a unit based on what? Coal gasses? Whow

Do you have any idea how dangerous what you are doing?

 

[berlin]

easy elk, i have a pretty good idea of what he has done and he should be fine. nothing to get too excited about. sounds like he simply needs more underfire air; coal bed is too dense. btw, the only way you get "orange" flame from anthricite is by forcing so much underfire air (aka too much draft) that the bottom ash is drawn up through the bed, and once heated by the blue flames above the fire, glows bright orange, thus rendering the blue flame not viewable. craig is right in that if you are running that much draft, you are not really burning anthricite correctly, although it may have worked for you, on most appliances it will greatly shorten the life to be fired so hard; i bet you were running rediculas egt's.

 

[laynes69]

The forced draft is low, trust me I don't want a blast furnace. Actually the power went out last night, when we were sleeping. We have the thermostat set for 72, when I woke up this morning, the house was 72. Its a very low draft, but just enough to draft the coal, no orange flames, just blue. I have debated this, but it is working well for me. I have thought of alot of different things that can go wrong, but there are alot of safetys here. I have that fan on a limit, so if its too hot it will shut down. Also once that fan shuts down, the fire will die down again, so it doesn't draft that hard all of the time.

 

[laynes69]

Well I put it back to where it was for factory installation. Its not made for anthracite. If the bed was as wide as the grates then I wouldn't have any problems, but the bed has a large taper at the top. I can burn soft coal just fine, but I have given up on the anthracite. The blower helped, but then the fire burned out quicker at the base which then starved the fire, just like it would before. That blower wasn't any good at all for a wood fire. You know I have at least 50 acres of wood to cut from which is all free. And having it installed properly I haven't had any issues. It burns wood awesome, but just not hard coal. So I took the time to put it back, 100% reversible. It was something to try, but if I ever update my wood furnace, I will consider something that will burn hard coal, or wood. I like the EPA wood furnaces, but I want to burn coal on those long cold nights. All is well now.

 

[coalkirk]

If the stoves not meant for anthracite, then you've made a wise choice to stop burning it. However several postings here describing how anthrcite should look when burning are not exactly correct. In a stove with natural draft, low blue flames are the norm. But a stove with a forced draft, you will have larger orange/yellow above the blue flames when firing and very low blue flames when idle.
Attached is a picture of my Harman boiler on a firing cycle. :coolsmile:

 

[seaken]

We've not had good success with combination stoves and furnaces over the years. Hard coal and wood burn differently and it's better to have a specific wood burner and a specific coal burner. Unless you can let the furnce go cold and then swap in a coal grate, magazine, and other coal specific parts, you're better off sticking with wood. If really want to burn coal buy a coal burning furnace.

 

[laynes69]

Its firebrick lined, and has cast iron inserts for front and back. Also has cast shaker grates. Its made to burn coal, soft but not hard. Dad bought it 20 years ago and he opted for the coal package so It would be a little heavier for burning wood. Im more than positive its the size and shape of the coal bed thats causing the problem. Its maybe 12 at the base of the grates, but tapers up to around 20 inches at the top. With a firebox this size, 1 little spin damper isn't going to allow for enough air.