Abstract: An automatic deliming process for a steam oven cooker is described. The process initiates a deliming procedure after a predetermined time of normal operation, which period of time is determined by the hardness of the water in the local area. Upon the expiration of this period of time a microprocessor signals an operator to shut down normal operation of the oven, and initiate the deliming process. The microprocessor then activates a peristaltic pump which injects a predetermined quantity of deliming liquid from an external reservoir into the generator. After the deliming time has passed and the generator contents have cooled to 140° F. the microprocessor automatically activates a drain pump to drain the deliming solution from the generator. Subsequently the microprocessor activates a fill-solenoid opening and inlet from a reservoir of rinse water into the generator to rinse the same. The microprocessor then again opens the drain to drain the rinse water, and normal operation is resumed.