Water storage device having a powered anode
View Patent ↗A dry-fire protection system and method. The dry-fire protection system includes a tank, a heating element, a powered electrode, a sensor, and a microcircuit. The heating element and the powered electrode are positioned in the tank, the powered electrode being positioned above the heating element. The powered electrode includes an electrode wire and a connector having an electrical connector coupled to the electrode wire, but electrically isolated from the tank, and a fastener for coupling the powered electrode to the tank. The sensor detects an electrical characteristic of a circuit formed by the tank, the powered electrode, and water in the tank. The microcircuit determines if a possible dry-fire condition exists based on a signal received from the sensor.
1. A method of controlling the operation of a water heater, the water heater comprising a tank, a heating element, an electrode, and a sensor configured to detect an electrical characteristic of a circuit formed by the tank, the electrode, and water in the tank, the method comprising:
applying a voltage to the electrode;
acquiring a signal from the sensor, the signal having a relation to the applied voltage;
determining whether the water heater is in a dry-fire state based on the acquired signal;
limiting activation of the heating element when the water heater is in a dry-fire state;
determining a conductivity of a fluid in the tank based on the signal when the water heater is not in a dry-fire state;
wherein the sensor includes a voltage sensor;
wherein the acquiring a signal from the sensor comprises sensing a potential of the electrode relative to the tank;
wherein the method further comprises ceasing application of the applied voltage;
wherein the sensing a potential occurs after the ceasing application of the applied voltage; and
wherein the determining whether the water heater is in a dry-fire state includes determining whether the sensed potential is less than a threshold, the threshold indicating a dry-fire state.
2. The method of claim 1 , wherein the sensor includes a current sensor, and wherein the acquiring a signal from the sensor comprises sensing a current applied to the tank.
3. The method of claim 2 , wherein the sensing a current occurs when the voltage is applied to the electrode.
4. The method of claim 1 , wherein the determining whether the water heater is in a dry-fire state includes determining whether the signal is less than a threshold, the threshold indicating the dry-fire state.
5. The method of claim 1 , wherein the sensor is electrically connected to at least one of the electrode and the tank.
6. The method of claim 1 , further comprising protecting the tank from corrosion by applying the voltage to the electrode.
7. A method of preventing activation of a heating element when a dry-fire condition exists in a water heater having a tank, a heating element positioned in the tank, a powered electrode positioned in the tank, and a controller, the method comprising:
applying an analog voltage to the powered electrode;
detecting a current having a relation to the analog voltage;
determining if the detected current is below a threshold;
isolating the heating element from a power source when the detected current is below the threshold; and
removing the analog voltage from the powered electrode and determining a conductivity of a system, including water in the tank, based on the detected current when the detected current is above a threshold and when the analog voltage is removed from the powered electrode.
8. The method of claim 7 , further comprising suspending the determining the conductivity of the system if the detected current is below a threshold when the analog voltage is removed from the powered electrode.
9. The method of claim 7 , further comprising generating a pulse width modulated signal and converting the pulse width modulated signal into the analog voltage.
10. The method of claim 9 , further comprising adjusting a duty cycle of the pulse width modulated signal based on a conductivity of a system including the tank and water in the tank.