120-240 volt solar controller is a thermostat that displays the temperature inside the Sunbank tank and powers the 240V (40G and 80G) auxiliary heating element. The controller comes with 150 ft sensor wire so that it can be mounted inside the house while monitoring the temperature inside the solar water heater. This controller also has a relay through which a pump can be powered to do both overheat protection and freeze protection. See the Sunbank Recirculation Valve and Pump listing for more information about this.
Requires a dedicated circuit if also powering the element.