Abstract: A pyrolytically cleaned oven includes an upper broil element and a lower bake element, the broil element is energized until the oven temperature reaches a trigger temperature, well below the glass transition temperature point of the oven porcelain enamel; then the bake and broil elements are alternately energized in a cyclical manner until an off temperature, somewhat above the trigger temperature but still below the transition temperature, is reached. Thereafter one or both of the elements are cycled to maintain the temperature with a range between the off temperature and a lower on temperature, also within the effective self cleaning range.

Abstract: A solid disk surface unit mounted in a glass or ceramic support surface, comprising a plate member of cast material with one or more resistive heating elements mounted to the underside thereof and a thermally conductive cover member enclosing the underside of the plate member with its peripheral edge in close thermal contact with the plate member near its periphery, is provided with a thermally responsive switching device thermally coupled to the cover member and adapted to respond to the surface temperature of the cover member at a point relatively remote from its peripheral edge. The switching device is operative to remove power from the resistive heating elements of the surface unit when the sensed cover member temperature exceeds a predetermined threshold temperature, thereby protecting the glass support surface from damage due to thermal stresses resulting from hot spots occurring near the periphery of the surface of the plate member.

Abstract: A start circuit arrangement for a microwave oven including a power control relay circuit which is independently responsive to a user actuable momentary start switch and to a programmed electronic controller to facilitate operation in a delay start mode. The relay circuit includes a start latch circuit, a door switch and an arm switch. User actuation of the momentary start switch sets the latch circuit. A signal from the electronic controller resets the latch circuit. The door switch is closed by closure of the oven door. The arm switch is closed by an arm signal from the electronic controller when an actual cooking cycle is to begin. The arm signal is removed upon expiration of the cooking cycle. The arm switch, start latch means and door switch are all operatively coupled to the relay such that the relay only enables energization of the power circuit for the oven when the arm switch and door switch are closed and the start latch is set.