Actually its not quite that easy. There is a system if you want it to work right.
First I have a coal NCB-250 Coal unit. For coal you need a shaker grate, and the air must come from under the coal bead. You also need a lot of fire bricks or the boiler will melt, warp.
You shake the grate twice a day to get rid of the cold ash, but don't shake it too much. Just 5 sec.
I put two logs on the side on hot red coals and load in the middle with new coal. If you just load coal you can suffocate the coal bed and the fire will go out.
The burning logs on the side will get the fire going strong and will leave an air hole for the new coal to ignite. And I put a log on top of the new coal load. So three logs total per day.
If the coal bed is weak because I haven;t loaded it for 2 days or so, I load it all wood with two shovels of coal in one corner. Than I load all coal once its burnt down 80%.
You also have to change the settings. Coal is like a train. Once it gets going when the fan turns off it will keep going and over heat. So you need to keep the diff as tight as can be. 3-5.
Mine is 175/5diff/pump on high. With that I get water temp 180/175.
If your setting are 185/12diff, you will get water temp 200/165 from the over shoot, and the coal needs more time to get going so the temp will keep dropping.
If you don't have a shaker grate, you can still add some coal, but I would add fire bricks if possible. I would add wood 60% on the boiler, than a few shovels of coal in the center, than wood. Once the coal is ignited just keep adding a little bit.
It will increase your hot ash time and add a lot of BTUs!!!.
So, if you go out of town and your wood is all our, the coal will still be hot. It's not uncommon that I go out of town for 3-4 days, and when I get back the water is still 155F, and I just throw wood on the ash and the fire is raging in 20 min.
Look at centrilia, PA. Coal fire still burning underground with hardly any oxygen for years.
When it's warmer 20+ I use more wood. If the windchill is under 20F I use the 3 logs and 90%coal combo. At -30F like it has been, wood burns like cardboard, and coal shines in performance. Just get high quality coal. The poor coal has a lot of sulfur and it smells awful. I use anthrocite, no smell at all and no smoke at all. It's expensive, but it;s worth it. I still spend less than the wear and tear in the chain saw, and car, etc. I do split about 2-3 cords a winter. I spend about $500 I think a year., but my house is very big, and we keep it 74+, but little use on chain saw, trailer and truck splitter.
I think this set up works when you are older, or too busy to handle 12-15 cords. You also do not need an elaborate set up for coal. Just dump it next to the boiler on concrete, and a tarp to cover. I don't even use a tarp. I just novel it in with snow on it.
the coal ash you can use under your fence wire, or on ice. The week will not grow arround the fence wire, and the ice will not be slippery and you done;t have to deal with the nastiness of salt.
JD,
Do you mix wood and coal by shoveling in coal on the wood.
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Topic: Ton=?cord (Read 10831 times)