Abstract: A step controller for a water heater includes a plurality of individual electrical elements to maintain a predetermined minimum temperature in accordance with a sensed temperature signal and a preset desired temperature signal in combination with a dead band signal. The heating elements are turned "on" and "off" in a random sequence whenever a change is required, and in accordance with a binomial distribution so as to substantially equalize the operating period of the heating elements. The controller includes a microprocessor unit to periodically sense the signals of a sensor and a preset potentiometer, and also operates to store the on-off status of the heating elements, each of which is assigned a binary load indentifying number. The microprocessor includes a psuedo-random binary number generator for generating the load identifying numbers.

Abstract: A controller for a water heater having a plurality of individual electrical heating elements changes the number of energized elements to maintain a predetermined minimum temperature. The number of "on" elements is related to the difference between sensed water temperature and a preset water temperature divided by a dead band factor. The heating elements are turned "on" and "off" in a programmed sequence whenever a change is required to optimize the equalization of operating time of the elements. The controller includes a microprocessor which monitors turn "on" or "off" of each element to continuously develop the "on" operational period of each element in relationship to all of the other heating elements since system initialization. The operation period is made relative to the load with the shortest period by substracting the lowest "on" time from all other loads so as to reduce the required memory size.

Abstract: A step controller for a water heater having a plurality of individual electrical heating elements changes the number of energized elements to maintain a predetermined minimum temperature. A thermistor sensor monitors the temperature of the water and generates a proportional signal. Preset potentiometers establish set point temperature signal and a dead band signal. The number of "on" elements is related to the difference between the sensed water temperature and the preset water temperature divided by the dead band factor. The heating elements are turned "on" and "off" in a predetermined sequence whenever a change is required. The sequence includes turning on the heating element which has been off for the longest period and turning off the heating element which has been on for the longest period.