- Energy-efficient multi-speed ECM blower motor - Heavy-duty stainless-steel, tubular heat exchanger - Stainless-steel secondary heat exchanger - Two-stage gas valve provides quiet, economical heating - Durable Silicon Nitride Igniter - Quiet two-speed induced draft inducer - Self-diagnostic control board with constant memory fault code - Color-coded low-voltage terminals with provisions for electronic air cleaner and humidifier - Low continuous fan speed options offer quiet air circulation - All models comply with California Low NOx emissions standards - Multi-position installation: upflow,horizontal left or right - Cabinet air leakage (QLeak) = 2%