The ratio of the electrical input power of a reference fan to the electrical input power of an actual fan at a given duty point (airflow, pressure, and air density), FEI considers motors and drives, not just fans, which makes it consistent with new efficiency metrics for pumps and air compressors.
AMCA-certified for sound and air performance, mixed flow model SQ is available in eight sizes, 16-33, with performance ranges up to 27,497 cfm and 3 inches wg.
Boiler FD fans tend to be complicated units with many components, including three or four control dampers, to regulate airflow at all firing conditions.