The Fenwal 01-018002-000 Thermo Switch is an HVAC safety and temperature control component designed to monitor system temperatures in compatible heating equipment. It works by automatically opening or closing an electrical circuit when a preset temperature is reached, helping regulate operation and protect critical components from overheating. Commonly used in furnaces, boilers, unit ... https://www.partshnc.com/01-018002-000-fenwal-thermo-switch-100-600f