- Heavy-duty stainless-steel,tubular heat exchanger - Stainless-steel secondary heat exchanger - Single-stage gas valve - Durable Silicon Nitride Igniter - Multi-speed blower motor - Quiet, single-speed induced draft blower - Self-diagnostic control board - Heavy-gauge steel cabinet with durable baked-enamel finish - Multi-position installation: upflow,convertible horizontal left or right - Cabinet air leakage (QLeak) = 2%