Fire door damper
The purpose of the fire door damper, which is located in the door of the fire box, is to allow a small amount of air to flow over the surface of the fire and thus aid combustion. When open, it also checks the draft through the fire.
Starting the fire
When starting a fire at the beginning of the season, have about two inches of ashes on the fire grates. On top of this place the paper and a good supply of kindling or charcoal. The ash pit damper should be wide open, the smoke pipe damper open, and the check damper closed. It is very important to get the best possible draft when starting the fire.
As soon as the kindling is burning well, put on a light covering of coal. Add more coal as soon as the first layer begins to burn. Do not try to add coal until the previous layer has ignited, as too much coal added too soon will smother the fire. The best heating results are obtained with a full fire pot. While this would seem to waste coal, it actually saves fuel in the long run. Also, a full fire pot is good insurance against the fire's going out and will save many trips to the furnace.
Build up the coal in the fire pot until it is level with the bottom of the fire pot door and sloping upward towards the rear of the furnace. When you have a good fire, set the dampers according to the amount of heat you want.
In mild weather
In the early fall and late spring, when it is usually necessary to heat the house only in the late afternoon and at night, the fire must be kept burning low enough during the rest of the day so that it will not make the house uncomfortable. To slow down the fire, keep a deep bed of ashes on the grate.
This will act as a damper and is accomplished by only shaking down the furnace occasionally. Have the check damper open, close the smoke pipe damper as far as possible without shutting off the draft completely, and close the ash pit damper.
The fire door damper should be open. If the weather turns suddenly cold, and you want more heat, shake down some of the ashes on the grate, add more fuel, close the check damper and open the ash pit damper. A smaller size coal is also useful in retarding the burning rate. Keep a supply of chestnut or pea size on hand for this purpose.
In cold weather
During very cold weather, it is important that the furnace deliver the maximum amount of heat at all times. This can be accomplished with little effort on the part of the operator.
At night, shake down the fire gently until a red glow can be seen from the ash pit. Now, with a hoe or some similar tool, rake the hot coals towards the door of the fire pot.
This bed of hot coals should slope down toward the rear of the furnace. Put fresh coal in the depression that has been formed. Leave a few inches of hot coals near the fire box door exposed. These will ignite the gas from the new coal and augment its burning. Add enough coal so that the fire will burn throughout the night and early morning.
Keep the level of the coal even with the bottom of the fire box door. The check damper and fire box damper should be open and the ash pit damper closed. As previously mentioned, the smoke pipe damper is only used to regulate the fire for seasonal changes.
In the morning, close the check damper, open the ash pit damper, and close the fire box damper. Allow the fire a few minutes to come up and then add coal to the level of the fire box door.
Do not shake the fire down unless it is necessary to make room for more coal. Rake the hot coals in the same manner as was done for night firing. To control the fire during the day, set the check and ash pit dampers. When full heat is required, close the check damper and open the ash pit damper.
The exact setting of the dampers is largely a matter of practice, of trial and error. You will soon learn just how far to open or close them.
Removal of ashes
If ashes are left to accumulate in the ash pit, they will not only cut down the flow of air to the fire but will also cause the fire grates to burn out. Taking the fine ashes out of the pit is an unpleasant task unless they are sprinkled with water to keep down the dust. A short length of garden hose can be attached to a nearby faucet and kept on hand for this purpose. Ashes should always be placed in a metal container and never in cardboard or wood.
Make it a practice to keep the basement as free of ashes as possible. They collect very rapidly and you will soon have a collection that requires several hours to remove. It is a good plan to remove ashes daily, or at least every other day.