The York S1-2702-311P Flame Sensor with a 90° bend is a critical safety component designed for gas-fired HVAC systems. It detects the presence of a burner flame by sensing electrical current through the flame, ensuring proper ignition. If no flame is detected, it signals the system to shut off the gas supply, preventing unsafe conditions. Commonly used in furnaces and heating units, it enhances operational safety and efficiency. This sensor helps reduce fuel waste, protects system components, and ensures reliable, consistent performance.