The Lochinvar & A.O. Smith 100340535 Sensor is a replacement sensing component designed to monitor operating conditions within compatible water heating equipment. It detects changes in temperature or system conditions and sends accurate signals to the unit’s control system, allowing the heater to regulate operation as needed. This sensor is used in compatible Lochinvar and A.O. Smith ... https://www.partshnc.com/100340535-lochinvar-ao-smith-sensor