These icemakers are very similar to the modular style icemakers in the previous section; the modular ones being a refinement of these machines. The water fill on these icemakers should be about 140 cc’s and take 7.5 seconds. There is a water level adjustment screw inside the cover. Some have water level adjustment dials on the right side of the plastic icemaker head cover.
The harvest cycle on these icemakers is thermostatically triggered. A thermostat inside the icemaker head is pressed against the ice mold. (When replacing the thermostat, use a dab of aluminum putty to insure good contact and heat transfer from the ice mold.)
Inside Compact Crescent Icemaker Head
When the mold gets down to about 17 degrees, the thermostat closes and starts the drive motor, and energizes the mold heater. Very shortly thereafter, a cam on the drive shaft closes the holding switch, keeping the motor circuit energized and turning even after the thermostat opens back up. The shaft rotates clockwise until the ejection fingers press against the ice. The motor then stalls, with the ejection fingers applying pressure to the ice, until the mold heats up enough for the cubes to separate from the mold. The fingers then continue pushing the ice out of the mold.
The thermostat stays closed throughout the first rotation of the ejection fingers. Near the completion of the first rotation, another cam attached to the driveshaft closes the fill switch, but water fill does not occur. The shutoff switch is closed, and offers a lot less resistance than the water valve circuit. Electricity will follow the path of least resistance, so the water valve will not open unless the thermostat is open.
Sometime during the second rotation of the ejection fingers, the thermostat opens and the mold heater shuts off, but the holding switch keeps the motor turning. Near the completion of the second rotation, the fill switch closes again for about 7-8 seconds, and this time the mold fills with water. Shortly after the fill switch opens, and waterflow stops, the holding switch opens. This stops the drive motor, and the icemaker is ready for another freeze cycle.
There is a third switch in the icemaker head; the shutoff switch. This switch is activated by the ice level sensor arm. If the ice level in the bin is too high, or if you raise the arm to the shutoff position, this switch opens and interrupts the thermostat circuit. The icemaker then will not enter a harvest cycle until the sensor arm is allowed to return to its full down position. During the harvest cycle, a cam raises the sensor arm and opens the shut-off switch, but the holding switch is still closed, which keeps the motor turning. After the ice drops into the bin, the sensor arm drops back down into the fully-lowered position and closes the shut-off switch unless the ice level prevents it.