Professional-grade Lennox 21L99 Flame Sensor is a critical OEM replacement part designed to maintain pilot and burner safety through precise flame rectification

This 120V gas control valve is engineered for natural gas (NG) applications

leak-free connection to 3/16" ID tubing

while the Gripnotch design supports smaller pulley diameters where traditional belts might fail

a mechanical internal failure is likely

Siemens Combustion SQM50.464R1Z3 Motor R-22 Professional-grade Lennox 21L99 Flame SensorThe Siemens SQM50. 464R1Z3 is a high precision reversing actuator motor engineered for the critical positioning of air dampers and fuel control valves in medium to large capacity burner systems. Operating at 120V, this robust unit features a multi input control board that natively supports 4 20mA, 0 135 ohm, and 0 10Vdc signals, providing internal flexibility for diverse combustion control architectures. With a nominal 140 lb in torque rating and a 25