8
RC454
A Guide To Burning Coal In Your Furnace
Furnaces that are capable of burning coal usually will burn both Bituminous and Anthracite coal. Anthracite is
perhaps the best coal fuel because of its long even burn time, high heat output, and cleanliness 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 expensive 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 (1-3/4” diameter to 4” diameter). When burning Anthracite, use “egg” or “broken” with sizes between
2-5/16” thru 4-3/8”. Note that it is important to the long life of your stove to buy coal which has been sized and
cleaned. Cleaning insures removal of rocks and other minerals. Never use coal smaller than 1” or larger than 5”
in diameter. Small sized coal will smother the fire. Too large a size of coal will not burn well.
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 resinous soft woods as kindling, with hard wood (oak, hickory, ash) added to
increase the heat prior to addition of the coal.
Before starting the fire, open the stove pipe damper (if equipped), 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 brightly. CAUTION: Never use gasoline, lantern fuel, kerosene, charcoal lighter
fluid, or other flammable liquids 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 result, 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 generally 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 experimenting with the individual setup as no two chimney’s or installations are going to be the same.
Just remember 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 careful 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 objective is to remove a small amount of the ashes without 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 center cone. Once
the volatiles are burned off, close the feed door and adjust the stove pipe damper, if equipped. Then adjust the
thermostat to the desired heat level.
More MAINTENANCE will be needed with bituminous 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 heavier 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.
Before adding further fuel, be sure to leave a red spot of glowing coals in the center of the firebox to insure that
the fire has not been smothered and to help ignite the gases given off by the new charge. A deep charge will
give a more even heat and a longer fire, but it may take one to two hours before the whole bed is fully ignited.
