The Williams Comfort Products P322391 Thermocouple is a temperature-sensing safety device used in gas-fired HVAC equipment. It generates a small electrical current in response to heat from the pilot flame, confirming flame presence and allowing the gas valve to remain open. If the flame fails, the thermocouple signal drops, shutting off gas flow to prevent unsafe conditions. Commonly ... https://www.partshnc.com/p322391-williams-comfort-products-thermocouple-w-junction-box