hI, NEWBIE here,

hi, Im Walter, in Lafayette, outside of newton, Trying to burn coal in my multi fuel outdoor wood burner, it burns wood, coal, so the dealer said, it has a shaker grate, and it also has separate chamber for burners for oil ,propane, or waste oil,
So far at best Ive only been able to burn a mix of firewood and coal, and the coal often get smothered in ash, I suspect that the coal get the water too hot, shut off the blower, and the system doesn't cool fast enough to turn on the blower to reignite the coal.
Im useing stove coal that I got from Wilson, in Sparta, the Dealer in Ohio told me he sells many tons of bituminus and it burn very well , but thats ohio, thats not available in NJ, is it. or desireable.

Can you post some pics of the grate & burn chamber? Do you plan on burning anthracite or bitumimous? For the most part, multi fuel boilers don't do that great a job at burning coal. Maybe yours is the exception. If we could see it we might be able to better give you suggestions.

Are you giving it air from underneath? Coal needs a lot of air from the bottom. How high are you filling the coal up? how much are you shaking down? etc....maybe step us thru what you are doing and then pointers can be given.

hi, there is power blower that is thermostat controlled by the water temperature which is set for 165 in the boiler, I cannot have it go higher or the hot air furnace in the basement trys to blow off the heat and just blows the heat into the house have had it go up to 95 degrees. and that also boils off the water in the system.
I suspect that I need to learn the right amount of coal vs thickness and time to balance this out with a minimum of wood that ashes it up

WAJAJAJA wrote:hi, Im Walter, in Lafayette, outside of newton, Trying to burn coal in my multi fuel outdoor wood burner, it burns wood, coal, so the dealer said, it has a shaker grate, and it also has separate chamber for burners for oil ,propane, or waste oil,
So far at best Ive only been able to burn a mix of firewood and coal, and the coal often get smothered in ash, I suspect that the coal get the water too hot, shut off the blower, and the system doesn't cool fast enough to turn on the blower to reignite the coal.
Im useing stove coal that I got from Wilson, in Sparta, the Dealer in Ohio told me he sells many tons of bituminus and it burn very well , but thats ohio, thats not available in NJ, is it. or desireable.

WAJAJAJA wrote:hi, there is power blower that is thermostat controlled by the water temperature which is set for 165 in the boiler, I cannot have it go higher or the hot air furnace in the basement trys to blow off the heat and just blows the heat into the house have had it go up to 95 degrees. and that also boils off the water in the system.
I suspect that I need to learn the right amount of coal vs thickness and time to balance this out with a minimum of wood that ashes it up

You migh already know this stuff but I hope it's worth bring up again so here goes... Mixing anthracite coal and wood generally does not promote good, steady or thorough combustion of either fuel. Having said that, I've read post where some operators are happy with the results. There are some physical and chemical realities to combusting the fuels both together and separately.

• Wood requires considerably less air to burn properly than anthracite. It also does best with a mix under and over fire air because it burns as coals and generates smoke. Fort the smoke to burn, it needs the proper amount of heat and extra over fire air to make the smoke bunt into flames. Under these conditions the anthracite mixed in might not burn fully.
  
• Conversely, setting the air for anthracite combustion could/will over fire the wood mixed in and generate a lot of heat very quickly while the anthracite burns along nicely. Since you've got forced combustion air, maybe this is what's happening when your furnace dumps the excess heat as a safety feature. For Anthracite to burn controllably it needs a deep bed. Most if not all of the air should be fed from below the grate. Anthracite has little volatiles (smoke) in it and is mostly carbon. The entire bed will ignite only if there is enough air fed from below and controlling the amount of air will control the heat output. I've played around and put a chunk of firewood ontop of a coal fire and it just sat there and charred without flaming. Once I fed more air, enough oxygen made it thru the burning coal and finally the piece of wood flamed off.

Welcome to the Forum.

thanks the replies, the last one, is right on the mark of what i have learned, over the cold spell, I havent mangaed to make it through the night on coal, but I can run a 12 hour day ok, I just need to practice and experience more. dont want to fall on the back up system, propane, too expensive. if I fail.

What size coal are you using? I have piles of assorted size coal, I have been picking the big stove coal size chunks out of it for 2 seasons now. Still learning what it takes to control a hand-fired stove. The more experienced guys here could advise about coal sizes, hope you get a chance to experiment! I got lazy last night and my fire went out by the time I got up in the morning. I start new fires with deadwood. Some cardboard, a few small branches, I let it catch and start putting anthracite in there with it. My fires tend to get ashbound after a few days, I usually poke the ashes from under the grate with a piece of bent steel. Still trying to keep up with it, and when I don't, I have to dump everything and start over. GOOD LUCK!

As others have said, you can't really mix anthracite and other fuels -- it burns differently than anything else and should be burned on its own once lit.

I burned nut anthracite in a multi-fuel furnace for a couple seasons. I found that you always need at least some combustion air -- not much -- or you're right that the fire will go out. From what it sounds like, you have a fan that goes on and off periodically to provide the combustion air. This may be OK for other fuels, but for coal you need constant draft. You may want to consider a rheostat on the combustion air fan so it blows constantly, just at a lower amount of air. If there's a way to control air in thermostatically, that'd be ideal. For instance, my furnace had a thermostat that opened and closed the inlet at the right time, though I set it up so it would never close fully, allowing the fire to always burn at least at an idle. If you have a way to allow even some natural draft when the fan isn't running, maybe this would help, too. Just be careful though as a little draft can go a long way and you don't want to overfire your unit!

I also found that the deeper the coal bed, the better (and longer) it burns. Typically you should be able to fill the firebox up to the top of the firebrick for the best burn.

The other tip I would have is to experiment with how you shake down the grates. First, don't wait too long before shaking -- you'll learn how long you can really wait before shaking will change from ash removal to a fire ending activity. Then, get the remaining coal burning hot (so shaking won't put the fire out). Last, experiment with how much shaking you really need to do. I was told shake till just a few burning coals drop down. I found with experimentation that with my furnace, it was actually better to shake until I had burning coals dropping through most of the grate. Any less and the grate system I had would leave too much ash and not allow enough air to keep the coal burning correctly. I can now keep a fire lit for weeks at a time. Each setup is different, and it will take some experimentation to get it right. Don't get discouraged, though, as it will take some time to learn the ins and outs of your particular setup. To be honest, it took a month or two of experimenting with my furnace before I really had the technique licked to get just enough ash out to keep the fire going for more than a week at a time. Keep us posted!

Hope things are working out for you.

Chris