The Lochinvar & A.O. Smith 100208544 Hi-Limit Outlet Sensor is a precision temperature safety device designed to monitor outlet water temperature in gas-fired HVAC systems. It works by continuously sensing temperature levels and signaling the control system to shut down operation if limits are exceeded, preventing overheating. Visit The Website: https://www.partshnc.com/hi-limit-ou... https://www.partshnc.com/hi-limit-outlet-sensor-3