The York S1-025-35354-000 Flame Sensor is a critical safety component designed to detect the presence of a burner flame in gas-fired HVAC systems. It works by sensing the flame through electrical conductivity, sending a signal to the control board to keep the gas valve open during proper operation. This flame sensor is commonly used in York furnaces and other compatible heating equipm... https://www.partshnc.com/flame-sensor-84