Bradford White Corp. said many of its power-vented, through-the-wall water heaters will be manufactured with the Defender Safety System® beginning Jan. 1, to comply with new ANSI standards regarding Flammable Vapor Ignition resistance. The new TTW water heaters feature a different version of the Defender Safety System combustion and control system, including a new spark-to-pilot ignition system and an integrated immersion gas control valve with an LED indicator to assist in troubleshooting. The new Defender design will be incorporated into 40- and 50-gallon TTW1 models and also into 50- and 65-gallon TTW2 models.