Fire Slowly Dies?

When I first start my coal fire, it burns hot and thoroughly-the ash is mostly dust. After about 24 hours, the lower grate cools off, solids begin to form, and the ashes contain unburned coal which have to be manually removed from the grate. Why does this happen?

Sounds as if your burning it wrong. Most people add coal and shake it in the morning and then repeat in the evening. You would have to provide some more details as to what your doing....

Well, I light a red hot wood fire then once it's going good, I add the coal. Even the lower grate turns red hot, and it burns efficiently. I shake only twice/day until red ash begins to fall, then add more coal and keep the air wide open until the new coal starts to outgas (blue flame), and I close door and set the air as required to keep a good hot fire.
As time goes on, however, the lower grate cools off, and solids begin to reach the grate-these solids contain unburned coal that I then have to remove mechanically or the fire will gradually go out. The only way around it is to let it go out, and start a new wood fire.
Help!

Possibly the coal is sub standard but I can't make that determination without seein it and even then I can't give a entirely accurate determination. You can't tell by how it looks all the time though, I've seen some pretty crappy looking stuff burn beautifully.

Is the coal that is not burning flat and dull on both sides? Possibly with seams of shiny coal running through it? Are they fused (melted) together when it reaches the bottom grate?

None of the conditions you describe seem to apply. The solids that reach the grate (cutting off the air supply) seem to have burned half way-the outside is ash, but if you hammer on them, the center is black, unburned coal! My stove is a 25 yr old Weso. Could air leaks around the fire box cause this condition? My fire box is not welded construction-it's assembled with a gasket like material between the parts.
Thanks for trying to help.

I have the same problem using a Harman Mark III. I cannot keep a coal fire going for 12 hrs unattended, maybe not 8 hrs. This will be my 4th season burning coal. When it dies, I have at quite a bit of unburnt coal left behind. I believe my problem lies within my flue. The Mark III has a 6" outlet. My flue is 8" x 34' high. My thinking is as the outside temps drop overnight, and the stove cools off a bit, my draft slows down allowing the fire to die. I typically would add a wood log on top of the fire at night in order to maintain a fire till morning. Does anyone believe my theory is correct? I am debating adding a 6" ss liner but at $550, I want to be sure this is the answer.

Comments appreciated,
Cap
Lehigh Twp, PA

Yes, a SS liner is reccomended. Sounds like both of you might not be shaking the ash out completely.

Another suggestion - just for laughs & giggles, crack a window open in the room where the stove is. If it is starving for air, you will experience what you describe. If the stove burns better with the window open, you need some more air brought in, easy enough to fix. (The open window is just a test, I am not suggesting burning with it open all the time)

Cap wrote:I have the same problem using a Harman Mark III. I cannot keep a coal fire going for 12 hrs unattended, maybe not 8 hrs. This will be my 4th season burning coal. When it dies, I have at quite a bit of unburnt coal left behind. I believe my problem lies within my flue. The Mark III has a 6" outlet. My flue is 8" x 34' high. My thinking is as the outside temps drop overnight, and the stove cools off a bit, my draft slows down allowing the fire to die. I typically would add a wood log on top of the fire at night in order to maintain a fire till morning. Does anyone believe my theory is correct? I am debating adding a 6" ss liner but at $550, I want to be sure this is the answer.

Comments appreciated,
Cap
Lehigh Twp, PA

Hi. I have the same problem. I get a hot fire going and then add coal. Start working toward getting enuff to last through the night. Think I have it and get up next morning it is out. Really gets disgusting. When it got down to 16 the other night , it did burn all night. I am using the 983 hitzer hand fired. What am I doing wrong. Thanks for your help.

Mlou wrote:Yes, a SS liner is reccomended. Sounds like both of you might not be shaking the ash out completely.

Another suggestion - just for laughs & giggles, crack a window open in the room where the stove is. If it is starving for air, you will experience what you describe. If the stove burns better with the window open, you need some more air brought in, easy enough to fix. (The open window is just a test, I am not suggesting burning with it open all the time)

Milou I have an 8" flue. Could that be my problem?????

Hi Guys,

I'm new myself to coal burning, been going about two months now with a new hand fired unit. My first week was just like you described with the fire going out & unburnt coal. It turned out that I wasn't putting enough coal in.

Someone in one of the earlier posts mentioned that he loaded his stove up to the top of the fire brick, so I tried that and it worked perfectly.

I HAVE A Harman SF250 HAND FIRED IF YOU CLICK ON THIS LINK YOU WILL SEE A PIC OF MY STOVE LOADED UP FOR THE NITE THE FIRE BRICK YOU SEE ARE 9" TALL

http://community.webshots.com/user/willijo847

YOU MAY HAVE TO COPY AND PASTE THE ADDRESS ABOVE

[email protected] wrote:When I first start my coal fire, it burns hot and thoroughly-the ash is mostly dust. After about 24 hours, the lower grate cools off, solids begin to form, and the ashes contain unburned coal which have to be manually removed from the grate. Why does this happen?

I have a clayton 1600 warm air furnace by us stove. I had the same troubles you were. The fire would start to go out after 12 hours. I would add coal and shake the grates but the fire would go out anyway. I talked to the guy I bought the anthracite off of and he told me to do the opposite of what I read on the internet. Take a staight pole and stick it through the fire to the grate. Do this in several different spots. then shake the grate until you can see the glow of the fire in the ash pan. He stressed not to stir the fire, just break up the ash that has fused by the grate. I burned mine for 48hrs before I had to let it go out due to warm outside temps. Also I fill the furnace to the top of the fire brick every time I refuel. Try this method and let me know how it works.

UPDATE TO MY EARLIER POST: I added a SS 6" liner to my 8" clay flue. This definitely allows me to burn longer and slower. Without the liner, my fire would slowly die as I described in an earlier post. With the liner, I can slow the draft down, burn long & slow.

My answer is to install a barometric damper (the type usually found on oil furnaces) I think that the draft in your stove may be too strong and the cool air is blowing past your coal and frying it, meaning the outside of the coal is burnt, but the inside isn't. A barometric damper will equalize the room air with the flue pipe air and help you out a lot. If your air intake sort of whistles when your stove is burning, then this is also a sign of a fast draft.

I forgot to mention that I use a Harman Mark 1. Ive had this stove for years and remember experimenting with it in the beginning. Sometimes from year to year, it helps to write down settings, stove pipe temps, surface temps, etc because when you get my age you forget from year to year. The other answer to the previous question is that it just may not be cold enough to run a sustained fire in your area. Once I get my stove stoked up, I almost dread a warm day or two. I like my stove so much it's like a pet. I look forward to running it nonstop. Am I crazy or what??