The Rheem Heat Exchange Thermistor, identified by part number RTG20212BC, is a critical component designed for use in Rheem tankless gas water heater systems. This specialized thermistor is engineered to monitor and regulate the temperature of the heat exchange process within the unit. By accurately measuring heat levels, it ensures efficient heat transfer and helps maintain optimal performance and safety of the water heating system. The RTG20212BC thermistor is specifically tailored for Rheem units, providing reliable temperature control for consistent hot water supply.