Abstract: A method and apparatus for determining a health status of a water heating device is disclosed. The water heating device may have a controller that incorporates logic to regulate the heater responsive to water temperatures detected at different areas within the water heating device by first and second sensors. Unfortunately, the first and second sensors may fail. To detect fault conditions or otherwise determine the heath status of the water heating device, a logic unit in the controller may perform a test on the first and/or second sensors so as to provide a test output. The logic unit may also determine whether the test output satisfies one or more predetermined thresholds. These predetermined thresholds may be indicative of a properly-functioning sensor. When the test output does not satisfy the at least one predetermined threshold, the logic unit may then set a fault condition indicative of improperly functioning sensors.

Abstract: A method of verifying proper operation of an electromagnetic valve. The method includes providing a mechanism to effect opening of the valve, verifying that the valve opened as a result of employing the mechanism to effect opening of the valve and after verifying the valve opened, signaling the valve to close after a first period of time has elapsed. The method further includes, after signaling the valve to close, signaling the valve to re-open after a second period of time has elapsed and detecting the occurrence or non-occurrence of an event associated with the closing or re-opening of the valve.

Abstract: In a process for fabricating a printed circuit board assembly carrying a chip on board type microcircuit package, aluminum wires are bonded to the aluminum pads on the microcircuit and to bare copper connector pads on the printed circuit board to form the electrical connection between them. The microcircuit, aluminum wires, and copper connection pads are then encapsulated with a material such as low stress liquid encapsulant having a thermal expansion coefficient approximately equal to that of the printed circuit board substrate material. Preferably the process includes steps of mounting the microcircuit and forming the copper connector pads on a printed circuit board laminate comprising cellulose epoxy mat such as CEM-1.

Abstract: A printed circuit board carries a microcircuit package electrically connected to bare copper connector pads on the printed circuit board microcircuit package by aluminum wires. The copper connection pads are encapsulated by a material such as low stress liquid encapsulant having a thermal expansion coefficient approximately equal to that of the printed circuit board substrate material. Preferably the printed circuit board laminate comprises cellulose epoxy mat such as CEM-1.