For T-4000 series units equipped with specialized security screws

this precision-molded component ensures your Nor East or vintage Honeywell/DeZurik valves maintain their specified shutoff class

It is technically identical to the Honeywell 4074ELR/U

providing superior thermal resistance in demanding industrial environments

Lennox 12F19 Flame Sensor For T-4000 series units equippedThe 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.