The Armstrong Furnace R40403-003 Blower Control Fan Timer Board is an essential component in HVAC systems, regulating the blower fan's operation to ensure optimal airflow. This board, which is present in furnaces and other HVAC devices, controls fan speed and timing to improve heating or cooling efficiency. It increases energy economy and guarantees constant comfort by timing the blow... https://www.partshnc.com/r40403-003-armstrong-furnace-blowercontrolfantimerboard