Bulletin rc454
a guide to Burning coal in your furnace
Furnaces that are capable of burning coal usually will burn both Bituminous and Anthracite coal. An- thracite is perhaps the best coal fuel because of its long even burn time, high heat output, and clean- liness which make it a good choice for the home. However, keep in mind it is a much more difficult fuel to use, requires more care and patience, is not so widely available, and is usually much more ex- pensive than Bituminous.
SIZE OF COAL:
Most sizes of Bituminous Coal will work in a coal furnace; for best results we recommend large “nut” coal to small “egg” coal
STOVE OPERATION:
All coal fires should be started with wood which will allow the fire to get hot enough to ignite the coal. The best ignition fires utilize dry pine or other resin- ous soft woods as kindling, with hard wood (oak, hickory, ash) added to increase the heat prior to ad- dition of the coal.
Before starting the fire, open the stove pipe damper (if epuipped), turn the thermostat to high, open the ash pit door and feed door, place newspaper and finely split kindling on the grate, light the paper, add larger hard wood after the kindling is burning bright- ly. Caution: Never use gasoline, lantern fuel, ker- osene, charcoal lighter fluid, or other flammable liq- uids to start or freshen up a fire in any heater. Place the larger pieces of wood on the fire so that they are slightly separated and form a level for the addition of coal. It will take 10 to 20 minutes before this wood is thoroughly ignited. Adding coal too soon will cut the air supply and smother the fire.
BURNING BITUMINOUS:
Once your kindling and wood fire has produced a bed of well established coals, start adding coal in layers allowing each to ignite before adding more. Bituminous has a high volatile content and, as a re-
sult, should be fired with the “conical method” - with the highest portion of your fire bed in the center of the firebox. The first flames will be long and gen- erally orange or yellow and produce quite a bit of smoke. As the gases burn off the flames become shorter, change color and produce less smoke.
Once the fire is WELL ESTABLISHED add coal to the center of the firebox forming the cone. Burning in this fashion allows heat to drive off the volatile gases, and turbulence created increases the burn efficiency. There will have to be some experiment- ing with the individual setup as no two chimney’s or installations are going to be the same. Just re- member to allow enough air to enter the firebox and keep the stove pipe damper open so that volatiles are properly burned. Before refueling, take the time to break up the cone a little with a poker, especially if it has caked over or formed a crust. But, be care- ful not to mix the coal as this increases the chances of forming clinkers. When shaking the grate(s) be gentle. Just a few short movements - a couple of “cranks” - is better than a lot of agitation. The objec- tive is to remove a small amount of the ashes with- out disturbing the fire. Stop when you see a glow in the ashes or the first red coals fall into the ash pan. Excessive shaking wastes fuel and can expose the grate(s) to very high temperatures which can cause warpage or burnout.
For overnight operation (long duration burn time) shake the fire and add coal, retaining the cen- ter cone. Once the volatiles are burned off, close the feed door and adjust the stove pipe damper, if epuipped. Then adjust the thermostat to the desired heat level.
More MAINTENANCE will be needed with bitumi- nous coal than with anthracite coal as more soot will collect on heating surfaces and in pipes, requiring more frequent cleaning.
ANTHRACITE:
Add a thin layer of coal (preferably smaller chunks) to the wood fire, being careful not to disturb it too much or cut off the draft. Then, add a second heavi- er layer after the coal is ignited and burning well. If necessary, add a third layer to bring the coal up to the top of the front liner (not above!). Be sure to close the ash door.
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