The Rheem Manufacturing Company–Ruud 47-20045-02 Auto Limit Switch (110°F–150°F) is a temperature-sensitive safety control designed to protect HVAC equipment from overheating. It automatically opens the circuit when temperatures exceed 150°F and resets once conditions return to a safe level near 110°F. Commonly used in furnaces, air handlers, and heating systems, it safeguards heat ex... https://www.partshnc.com/110-150f-auto-limit-switch-7