Flame Guard and Flame Lock Gas Water Heaters are made by American Water Heater Company and sold under the names American Proline, Whirlpool, Envirotemp, Mor-Flo, Powerflex, Premier Plus, US Craftmaster and possibly others. The Flame Guard and Flame Lock are names for FVIR (Flammable Vapor Ignition Resistant) Technology designed and manufactured by American Water [...]