- Energy-efficient multi-speed ECM blower motor - Heavy-duty Million Air stainless-steel, dual-diameter tubular heat exchanger - Stainless steel secondary heat exchanger - Two-stage convertible gas valve automatically adjusts to high or low stage - Durable SureStart 110 volt Silicon Nitride Igniter - Quiet single speed draft inducer - Self diagnostic control board with constant memory fault code - Low continuous fan speed options offer quiet air circulation - Multi position installation: upflow,horizontal left or right - Cabinet air leakage (QLeak) = 2% - Heavy gauge steel cabinet with durable baked enamel finish