How the Defender Safety System® Works

During normal operation, air for combustion is drawn into the water heater through the opening in the jacket. This air travels down and around t he combustion chamber and enters through holes in the very bottom of the corrosion-resistant combustion chamber. The air then travels up through the oriented flame arrestor plate louvers, where the velocity of the air is increased and its direction altered. The air then mixes in a normal manner with the supplied gas and is efficiently combusted, producing very low NOx emissions. In the case where trace amounts of flammable vapors are present in the air flowing into the combustion chamber, the burner or pilot flame harmlessly ignites the vapors.

If flammable vapors are in sufficient quantity to prevent normal combustion the burner and pilot flame is shut down. Should the flammable vapors continue to the burner, the flame arrestor plate prevents the flames from traveling backwards and igniting vapors outside of the combustion chamber. The calibrated, multipurpose thermal switch recognizes this and shuts down the pilot and main burner. This switch also deactivates the burner and pilot in the unlikely event of restricted airflow caused by severe lint, dust or oil accumulation on the arrestor plate.

The heart of Bradford White’s Defender Safety System® is the flame arrestor design of the patented ScreenLok® Technology. This precisely engineered and manufactured component is made 304L alloy stainless steel and contains up to eighteen thousand, geometrically oriented louvers. These micr o dimensioned louvers increase the velocity of incoming air to the system. If flammable vapors enter this uniquely designed system and are ignited, a vector effect occurs inside of the combustion chamber. The combination of high velocity air entering the chamber and the vector effect caused by combustion will prevent any flames present in the chamber from traveling backwards through the flame arrestor plate and outside of the water heater.

The Bradford White Defender Safety System® maintains outstanding efficiency, a long service life and very low NOx emissions. Best of all, it provides maintenance free operation while meeting the stringent ANSI standard for the affected gas water heaters.