The Nordyne 903476 Heat Exchanger is a replacement component designed to transfer heat from combustion gases to the circulating air in compatible gas furnaces. During operation, the furnace burner heats the exchanger, while the blower moves air across its surfaces, delivering warmed air through the ductwork. This heat exchanger is used with compatible Nordyne gas furnace systems to su... https://www.partshnc.com/903476-nordyne-heat-exchanger