An atmospheric burner is a gas flame ignition device that draws combustion air directly from the surrounding environment through natural draft rather than forced air. These burners rely on gravity and buoyancy to pull air into the combustion chamber, making them simpler and less expensive than power burners. They typically operate at 80 to 85 percent efficiency.
Design and Operation
Atmospheric burners feature a primary air shutter that controls the amount of air mixed with gas before combustion. The Venturi tube creates a vacuum that draws approximately 25 to 35 percent of required combustion air, with the remainder supplied from the furnace cabinet. No blower or inducer is needed, reducing mechanical complexity.
Applications and Limitations
These burners suit residential furnaces in areas with adequate air supply and natural draft conditions. They perform well in naturally vented systems but cannot be used with sealed combustion or high-efficiency furnaces. Atmospheric burners are being phased out in many jurisdictions in favor of more efficient condensing models that achieve 90 to 98 percent efficiency.