Home refrigerator ice makers, like those manufactured by Amana, work by using electrical circuitry and switches to progress through the steps required to make ice. Each step is automatically triggered by the completion of the previous step.
When the ice maker is first turned on, it begins the ice-making process by opening a valve that permits the flow of water into an ice mold. The valve opening is timed so that only the proper amount of water can flow into the mold. The water is then frozen by the refrigerator's cooling unit. The ice maker uses its own internal thermostat to determine when the ice is ready. After this thermostat detects that the temperature has dropped low enough to freeze the water, the ice maker warms the ice slightly with its built-in heating coil. This makes it easier for the ice to be removed from the mold.
After the ice has been warmed, the ice maker's motor activates. This motor powers gears and blades that remove the ice from the mold. The ice is pushed by the blades into plastic notches that break the ice into small pieces and place them in the dispensing area, where the ice waits to be put to use. There is a plastic arm inside the dispenser that is gradually lowered as the dispenser is emptied. When the plastic arm is in its lowest possible position, this triggers the ice maker to begin the whole process again.