The Lochinvar TSD91C1 48-21 Flue Temperature Sensor Kit is a genuine OEM replacement component designed to monitor flue gas temperatures in Lochinvar water heating systems. This sensor ensures safe and efficient system operation by detecting overheating conditions and triggering appropriate control responses to protect the unit. Key Features OEM Lochinvar flue temperature sensor kit Monitors exhaust flue gas temperatures for safety and efficiency Helps prevent overheating and system damage Compatible with select commercial water heaters Includes necessary installation components Specifications Part Number: TSD91C1 (also known as 48-21) Type: Flue Temperature Sensor Kit Application: Safety and temperature monitoring in flue/exhaust systems Function: Sends temperature data to the control board Compatible Models Lochinvar SWA500 Lochinvar SWR125 Why Choose This Item Choose the Lochinvar TSD91C1 Flue Temperature Sensor Kit to maintain safe operation, prevent overheating, and ensure regulatory compliance in your water heater system. With OEM quality, reliable performance, and accurate monitoring, it?s the ideal solution for protecting your equipment and optimizing efficiency.