Columbia Installation and Operation Manual
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4.3.5 Turning Down the Air Supply
Once the firewood, firebox and chimney are hot, you can begin to reduce the air supply for
a steady burn.
As you reduce the air supply to the fire, two important things happen. First, the firing rate
slows down to spread the heat energy in the fuel over a longer period of time. Second, the
flow rate of exhaust through the stove and flue pipe slows down, which gives more time for
the transfer of heat from the exhaust. You will notice that as you reduce the air setting, the
flames slow down. This is your indication that the stove is burning at its peak efficiency.
If the flames get small and almost disappear when you turn down the air, you have turned
down the air too early, or your firewood is wetter than it should be. With good fuel and
correct air control use, the flames should slow down, but should stay large and steady,
even as the air supply is reduced.
4.3.6 Building Different Fires for Different Needs
Using the air control is not the only way to match the stove’s heat output to the heat
demand. Your house will need far less heat in October than in January to be kept at a
comfortable temperature. If you fill the firebox full in fall weather, you will either overheat
the space or turn the stove down so much that the fire will be smoky and inefficient. Here
are some suggestions for building fires to match different heat demand.
4.3.6.1 Small Fires to Take the Chill Off the House
To build a small fire that will produce a low heat output, use small pieces of firewood and
load them crisscross in the firebox. The pieces should be only 3” to 4” in diameter. After
raking the coals, you can lay two pieces parallel to each other corner to corner in the
firebox and lay two more across them in the other direction. Open the air control fully and
only reduce the air after the wood is fully flaming. This kind of fire is good for mild weather
when you are around to tend the stove and should provide enough heat for four hours or
more. Small fires like this are a good time to use softer wood species so there will be less
chance of overheating the house.