Patent ID: 7469840

Claim:
A controller for controlling the operation of a gas-fired water heating appliance, the controller comprising: a switching means for connecting an electrical power source to an igniter for igniting gas; a voltage sensing means for sensing the voltage value of the electrical power source, the voltage sensing means comprising a first voltage comparator that provides an output representative of the voltage level of the power source, and also a second voltage comparator that provides an output representative of the voltage level of the power source; and a control means comprising a microprocessor having first and second analog-to-digital inputs connected to the first voltage comparator and second voltage comparator, wherein the microprocessor determines the actual voltage level of the power source for determining whether the power source is of a first rated voltage level or a second rated voltage level, and responsively determines a switching sequence corresponding to either the first rated voltage or the second rated voltage, where the microprocessor controls the switching means based on the switching sequence to effect switching of power to supply an average predetermined voltage to the igniter that will heat the igniter to a desired temperature, and where the microprocessor locks out igniter operation when there is a disagreement between the voltage levels sensed by the first and second voltage comparators.