Lennox 12F19 Flame Sensor meaning it will automatically close

meaning it will automatically close the circuit once the sensed temperature falls below the reset point

Using a standard socket wrench

preventing the operation of the gas valve if flue gas venting is obstructed or the inducer blower fails

long-term monitoring solution with no moving parts to fail in high-vibration environments

Precision Safety: High-sensitivity vent safety switch detects flue blockages to prevent CO poisoning

Lennox 12F19 Flame Sensor meaning it will automatically closeThe Lennox 12F19 Flame Sensor is a critical safety component designed for precise flame rectify detection in residential and commercial gas fired heating systems. This genuine OEM part is engineered to monitor the burner's pilot or main flame, sending a continuous microamp signal to the furnace control board. If the 12F1901 furnace sensor fails to detect a flame, it immediately signals the gas valve to shut down, preventing hazardous gas accumulation.