The Reznor 146465 Auto Fan Limit Switch is a temperature-sensitive control component designed to regulate blower operation and protect heating equipment from overheating. It works by monitoring internal temperatures within the heating unit, automatically activating the fan when the desired temperature is reached and shutting down the burner if excessive heat is detected. Commonly used in furnaces, unit heaters, and other HVAC heating systems, this switch enhances safety, supports efficient airflow management, improves system reliability, and helps maintain consistent heating performance while reducing the risk of equipment damage.