ICE MACHINES Q-Model Service Manual

Section 5Water System Ice Making Sequence of OperationNOTE: The sequence of operation is the same for selfcontainedand remote models.INITIAL START-UP OR START-UP AFTERAUTOMATIC SHUT-OFF1. Before the ice machine starts, the water pump andwater dump solenoid are energized for 45 secondsto purge old water from the water trough. Thisensures that the ice-making cycle starts with freshwater. The water fill valve energizes after the 45-second water purge, and remains on until the waterlevel probe is satisfied.FREEZE CYCLE2. To pre-chill the evaporator, there is no water flowover the evaporator for the first 30 seconds of thefreeze cycle.3. The water pump starts after the 30-second pre-chill.An even flow of water is directed across theevaporator and into each cube cell.During the first 45 seconds of the Freeze Cycle, thewater fill valve cycles on and off as many times asneeded to refill the water trough.After the 45 seconds, the water fill valve cycles onand off one more time to refill the water trough. Thewater fill valve then remains off for the duration ofthe Freeze Cycle.WATER INLET VALVE SAFETY SHUT-OFFThis feature limits the water inlet valve to a six-minute ontime. Regardless of the water level probe input, thecontrol board automatically shuts off the water inlet valveif it remains on for 6 continuous minutes.TO DISTRIBUTION TUBEWATER INLET VALVEWATER DUMP VALVEWATER PUMPTO DRAINSV1677Figure 5-1. Water Flow Over the EvaporatorPart No. 80-1100-3 5-1