Lochinvar & A.O. Smith 100170487 Upper Sensor 321042-401 Standardized Fit: The 1/4-20" threaded

Standardized Fit: The 1/4-20" threaded shaft and 22-inch leads allow for direct replacement in HVAC fan motor assemblies

providing a clean and secure professional finish

By choosing a genuine furnace heat exchanger replacement

Integrated Auxiliary Switch: The internal SPDT switch simplifies the wiring of end-stop verification or secondary equipment triggers

Includes the critical low-pressure switch to safeguard against fuel supply drops

Lochinvar & A.O. Smith 100170487 Upper Sensor 321042-401 Standardized Fit: The 1/4-20" threadedThe Lochinvar & A. O. Smith 100170487 Upper Sensor (formerly TST1187) is a critical thermistor based component engineered for high precision temperature monitoring in residential and commercial water heaters. As a direct immersion NTC temperature sensor, it provides real time resistance feedback to the control board, ensuring the appliance maintains optimal setpoints while preventing dangerous high limit conditions. This OEM water heater sensor is