The Amtrol 940R101 is a water heater smart control with thermistor for Amtrol WH, TD, and WHS models. The 940R101 supplements Amtrol water heater models with mechanical dial controls with a more user-friendly digital control. This device features an intelligent memory saving system that eliminates post-outage resets along with diagnostic error codes to assist in troubleshooting. The 940R101 features 24 to 120 volt input operation as well as low-voltage capability to protect against heating system shut down during power outages. Color coded wires on the 940R101 allow for quick and easy installation.