The Adjustments of an Air Damper on the Ash Door of a Wood Stove

Draft

• The damper on the stove’s ash door controls the air flow to the fire’s base. During normal operation, the heat produced by the fire inside the stove escapes through the chimney. The movement of heated air up through the chimney creates a partial vacuum at the damper openings, through which fresh air is drawn feeding combustion inside the stove. Opening the damper allows more air to enter the firebox, increasing the fire’s heat. Closing the damper reduces the amount of air available for feeding combustion and reduces the amount of heat produced. Exercise caution while adjusting the damper toward the closed position. Completely cutting off the air supply causes the fire to smolder and produce excessive smoke.

Balancing Act

• While the damper on the ash door controls the amount of air feeding the base of the fire, the damper on the stove’s fuel door controls the amount of air available for combustion of gases released as a wood fire’s byproduct. Increasing the airflow to the fire’s top reduces the amount of solid emissions in the form of smoke, and increases the temperature inside the stove. When the dampers are properly adjusted, there should be little or no visible smoke coming out of the chimney.

Maintenance

• In order for your stove to operate efficiently, frequently empty the ash pan. When ash accumulates to the level of the grate, airflow is restricted and the ash door’s damper becomes ineffective. Restricted airflow over the grate can cause damage and premature failure from overheating the stove’s internal cast iron parts, because the flow provides a certain amount of cooling as well feeding the fire.

Starting a Fire

• Leaving the ash door open when starting a fire can damage the stove. Allowing too much air into the stove dramatically increases the fire’s temperature. Overheating the stove’s interior components reduces their useful life. When starting a fire, open the ash door damper completely. Once the fire is going, adjust the damper to control the rate of combustion.

Ideal Operation

• Use only dry, seasoned wood for your stove’s the best performance. Wet or green wood produces large amounts of smoke regardless of the damper settings. Excessive smoke creates dangerous creosote buildups that can cause chimney fires. Smaller fires allow greater air circulation inside the firebox and produce combustion that is more efficient. Whenever possible, feed the fire frequently and place only one or two pieces of wood in the stove at a time.