Unburned Nut Coal in Grate

I've been burning nut coal for a week or so in a small Chappee wood/coal stove. Burning coal is new to me but I seem to have grasped the fundementals: I can quickly get the coal fire going, generously bank it, turn down the draft, and I have nice steady heat (my flue-pipe thermo reads 350-400F) that lasts for hours. Problem is, I have a lot of unburned coal the next day on the grate (not in the pan). The outside of the coal nut is burned but if I crack it open, it's virgin inside. What am I doing wrong? I've tried smaller and larger amonts of air/draft with the same end results. Shaking/not shaking doesn't seem to help either.

If I let my fire die it will look like what you are describing,but if I keep it going(adding more coal)those unburnt coal pcs. get burnt.
Also if you build your new fire in between or on top of left overs they will get consumed,this is my take on your fire without seeing it.How long of a burn are you getting?
Also see thread in this section called uneven burn,it may shed some light.

Most people burn continuously 24/7 for the entire season(or in my case the furnace has been running about 25 years ), you should try getting on a schedule. Most stoves will go 12 hours, shake and load once in the morning and once at night, **then let it be. If you have a smaller stove it may not last that long so maybe a 8 hour schedule or however it works out.

If you're only firing it for few hours to tell you the truth I don't know if that is worth it, kinda like starting and stopping your car every time you get to a light.

Does it look like this?

http://www.c20fires.co.uk/stoves/s034.htm

I try to keep it burning but it goes out by itself after 4-5 hours without warning.

Looks similar, but mine's front-loading. Same size though. Maybe it's only ment for wood?

Hello tilac, welcome to the forum. I'm not familiar with your model of stove. Is there combustion air entering above the fire?? For athracite all combustion air must come in under the fire, through the grates.

When you say 'generously bank' the fire, what do you mean?? If you mean a deep load of coal in the firebox, then that is good. If you mean a load of coal with a steep slope or bank, then the lower end of the fire may burn down to the grate, exposing a way for the air to bypass the coal, allowing the fire to go out.

Hope this helps. Greg L

Can you post a photo of the firebox, grate and draft controls?? This will help us help you.

GL

Tilac999, what I have found out from this forum and now through experience is a good deep bed is good. But as the bed gets lower the fire, even though it is still burning, gets weaker. Unlike wood that will just keep burning right down to the last match stick, coal needs a good bed of fuel at all times. I can get a good 14 hour burn out of my Mark III, but the fire is fragile at that point and I must baby it to get it back up. If the fire is allowed to burn down to nothing then there will be a layer of unburnt coal. Trust me, once you get use to the differences in burning coal as opposed to burning wood, the only time you will burn wood is to start the coal.
Tom

That stove I believe is made in England. It may burn bituminous well but also may be very difficult to burn anthracite in due to it's design. Refer to LsFarm's post on the matter.

Thanks for the replies. Yup, my draft is below and air comes up from under the grate/coal. Also, I believe my Chappee is a French stove from what I have read. When I say I bank the coal, I mean I slowly build up a 3-4 inch deep bed filling the entire area of the stove. I just don't understand why it dies out after making good heat. I'd love to get more than a 4-6 hour burn, especially considering how much coal I'm using to fill the stove.

tilac999 wrote:When I say I bank the coal, I mean I slowly build up a 3-4 inch deep bed filling the entire area of the stove. I just don't understand why it dies out after making good heat. I'd love to get more than a 4-6 hour burn, especially considering how much coal I'm using to fill the stove.

3 or 4 inches I have a problem with, I don't know your stoves size or firebox shape, but that just doesn't sound very deep. Once you have established a good anthracite fire you need to fill it to the very top of the firebrick. Don't be shocked by the amount of coal it takes. When I start my boiler it takes about 80#-100#. Yet I can run it on 25#-50# a day once it is going in 35F + weather.
If you aren't filling it up, that's your problem.

OK, thanks. I'll try making a MUCH deeper bed and see how it goes. Report back later.

This morning it was 15F and I made a coal fire with a VERY deep bed. I loaded as much coal as I could fit into the stove and it burned real nice all day 9+ hours. I now see that the depth of the coal bed is the secret. Thanks for all your helpful advice.

tilac999 wrote:I now see that the depth of the coal bed is the secret.

OK, repeat after me,"the only thing wood is good for is starting a coal fire".

You have to forget everything you know about wood as it doesn't work that way with anthracite. You can build and kill 6 woodfires in a day. But it actually takes about two days to build a proper anthracite bed. It will only burn from the bottom up, and all the air must come in from the bottom. With wood, anything that gets air will burn in the firebox. With the coal you need to build 3 layers. Your first day or so is burning up a lot of coal to build a bed ash, which you need to control the burn. Above that you'll have a layer of glowing coals, banging out some serious heat. And finally, a layer of fresh coal warming up to take over next round. You don't start a coal fire, you build it. It will be there for you.

It almost sounds like you don't do anything but keep filling it up with coal. Is that right? Any shaking or raking? The coal fires I started seemed to get worse if I tried to gently shake down any ashes. Leave it alone?