The Carrier 338085-408 Limit Switch (210°F–20°F) is a safety control device used in gas furnaces and heating systems to monitor temperature limits. It opens or closes electrical circuits based on measured temperatures, preventing overheating by shutting down the burner when temperatures exceed safe thresholds and resetting once conditions normalize. https://www.partshnc.com/338085-408-carrier-l210-20f-limit-switch