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BURNING PROCESS | Final Stage |
In recent years there has been an increasing concern about air quality. Much of the blame for poor air quality has been placed on the burning of wood for home heating. In order to improve the situation, we at
Kindling or First Stage
It helps to know a little about the actual process of burning in order to understand what goes on inside a wood burning appliance. The first stage of burning is called the kindling stage. In this stage, the wood is heated to a temperature high enough to evaporate the moisture which is present in all wood. The wood will reach the boiling point of water (212°F) and will not get any hotter until the water is evaporated. This process takes heat from the coals and tends to cool the appliance.
Fire requires three things to burn - fuel, air and heat. So, if heat is robbed from the appliance during the drying stage, the new load of wood has reduced the chances for a good clean burn. For this reason, it is always best to burn dry, seasoned firewood. When the wood isn’t dry, you must open the air controls and burn at a high burn setting for a longer time to start it burning. The heat generated from the fire should be warming your home and establishing the flue draft, not evapo- rating the moisture out of wet, unseasoned wood, resulting in wasted heat.
The air control in the right side of the grille, bottom rod, is called the
Second Stage
The next stage of burning, the secondary stage, is the period when the wood gives off flammable gases which burn above the fuel with bright flames. During this stage of burning it is very important that the flames be maintained and not allowed to go out. This will ensure the cleanest possible fire. If you are adjusting for a low burn rate, you should close down the air to the point where you can still maintain some flame. If the flames tend to go out, it is set too low for your burning conditions. The air control, located at the right of the grille, top rod, is the one used to adjust for burn rates. This is called the Primary Air Control. Figure 19A.
The final stage of burning is the charcoal stage. This occurs when the flammable gases have been mostly burned and only charcoal remains. This is a naturally clean portion of the burn. The coals burn with hot blue flames.
It is very important to reload your appliance while enough lively hot coals remain in order to provide the amount of heat needed to dry and rekindle the next load of wood. It is best to open the air controls for a short while before reloading. This livens up the coal bed. Open door slowly so that ash or smoke does not exit appliance through opening. You should also break up any large chunks and distribute the coals so that the new wood is laid on hot coals.
Air quality is important to all of us, and if we choose to use wood to heat our homes we should do so responsibly. To do this we need to learn to burn our stoves in the cleanest way possible. Doing this will allow us to continue using our wood stoves for many years to come.
AIR CONTROLS
Start-up System
The combustion air enters at the rear of the firebox through the rear air tubes. This air supply is controlled by the Start-
up Air Control.
Primary Air System
The primary air enters at the upper front of the firebox, near the top of the glass door. This preheated air supplies the necessary fresh oxygen to mix with the unburned gases, helping to create second, third and fourth combustions. This air is regulated by the Primary Air Control. For more primary air push control “IN”, for less air pull control “OUT”.
Primary Air Control
Figure 19A | OPEN - PUSH IN |
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| CLOSE - PULL OUT |
September 1, 2008 | Page 19 |
