Patent attributes
A water heater having a powered electrode and a method of controlling the water heater. The water heater includes a tank to hold water, a heating element, an electrode, and a control circuit. The control circuit includes a variable voltage supply, a voltage sensor, and a current sensor. The control circuit is configured to controllably apply a voltage to the electrode, determine the potential of the electrode relative to the tank with the voltage sensor when the voltage does not power the electrode, determine a current applied to the tank after the voltage powers the electrode, determine a conductivity state of the water in the tank based on the electrode potential and the current, and define the voltage applied to the powered electrode based on the conductivity state. The control circuit of the water heater can also determine whether the water heater is in a dry-fire state.
