Aos Holding Company

David E Morris

Ray Oliver Knoeppel

Thomas Gerard Van Sistine

Jason W T Scott

A fluid-heating apparatus for heating a fluid and method of operating the same. The fluid-heating apparatus includes a heating element for heating a fluid surrounding the heating element and a control circuit connected to the heating element and connectable to a power source. The control circuit is configured to determine whether a potential dry-fire condition exists for the heating element. In one implementation, the method includes applying a first electric signal to the heating element, detecting a first value of an electrical characteristic during the application of the first electric signal, applying a second electric signal to the heating element, applying a third electric signal to the heating element, detecting a second value of the electrical characteristic during the application of the third electric signal; and determining whether a potential dry-fire condition exists based on the first and second values.

Fluid-heating apparatus, circuit for heating a fluid, and method of operating the same

A fluid-heating apparatus for heating a fluid and method of operating the same. The fluid-heating apparatus includes a heating element for heating a fluid surrounding the heating element and a control circuit connected to the heating element and connectable to a power source. The control circuit includes a current path from the power source to the heating element back to the power source, a switch connected in the current path, and a current sensor. The method includes initiating a heating state of the fluid-heating apparatus, initiating a non-heating state of the fluid-heating apparatus, applying a voltage to the heating element during the non-heating state, sensing a leakage current of the heating element during the application of the voltage, and determining a degradation of the heating element with the sensed leakage current.

A fluid-heating apparatus for heating a fluid and method of operating the same. The fluid-heating apparatus includes a heating element for heating a fluid surrounding the heating element and a control circuit connected to the heating element and connectable to a power source. The control circuit is configured to determine whether a potential dry-fire condition exists for the heating element. The method includes applying a first electric signal to the heating element, detecting a first value of an electrical characteristic during the application of the first electric signal, applying a second electric signal to the heating element, applying a third electric signal to the heating element, detecting a second value of the electrical characteristic during the application of the third electric signal; and determining whether a potential dry-fire condition exists based on the first and second values.

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Racine, WI, United States of America

David E Morris