The Solatherm control unit regulates DC electricity generated by a photovoltaic array and applies it to a resistive heating element, located in a storage hot water vessel, to generate hot water. The microprocessor constantly monitors the water temperature in the storage vessel and energizes the heating element when sufficient power is available from the array and the water stored in the vessel is below the set temperature. (Factory set temperature 600 or 700 Celsius) When the temperature is reached the unit will turn the element off until the water temperature falls.
Once the water is up to temperature, Solatherm units with redirect are able to redirect surplus power for another purpose such as battery storage. The controller monitors the temperature of the stored water to ensure maximum hot water is maintained.