ICE MACHINES Q-Model Service Manual

Electrical System Section 6Water Level Control CircuitryWATER LEVEL PROBE LIGHTThe water level probe circuit can be monitored bywatching the water level light. The water level light is onwhen water contacts the probe, and off when no water isin contact with the probe. The water level light functionsany time power is applied to the ice machine, regardlessof toggle switch position.FREEZE CYCLE CIRCUITRYManitowoc’s electronic sensing circuit does not rely onfloat switches or timers to maintain consistent waterlevel control. During the freeze cycle, the water inletvalve energizes (turns on) and de-energizes (turns off) inconjunction with the water level probe located in thewater trough.During the first 45 seconds of the Freeze Cycle:• The water inlet valve is on when there is no water incontact with the water level probe.• The water inlet valve turns off after water contactsthe water level probe for 3 continuous seconds.• The water inlet valve will cycle on and off as manytimes as needed to fill the water trough.After 45 seconds into the Freeze Cycle:The water inlet valve will cycle on, and then off one moretime to refill the water trough. The water inlet valve isnow off for the duration of the freeze sequence.HARVEST CYCLE CIRCUITRYThe water level probe does not control the water inletvalve during the harvest cycle. During the harvest cyclewater purge, the water inlet valve energizes (turns on)and de-energizes (turns off) strictly by time. The harvestwater purge adjustment dial may be set at 15, 30 or 45seconds.CONTROL BOARDSV1616Figure 6-25. Freeze Cycle Water Level SettingDuring the freeze cycle, the water level probe is set tomaintain the proper water level above the water pumphousing. The water level is not adjustable. If the waterlevel is incorrect, check the water level probe fordamage (probe bent, etc.). Repair or replace the probeas necessary.WATER INLET VALVE SAFETY SHUT-OFFIn the event of a water level probe failure, this featurelimits the water inlet valve to a six-minute on time.Regardless of the water level probe input, the controlboard automatically shuts off the water inlet valve if itremains on for 6 continuous minutes. This is important toremember when performing diagnostic procedures onthe water level control circuitry.HARVESTWATER PURGEADJUSTMENT30 45NOTE: The water purge must be at the factory settingof 45 seconds for the water inlet valve to energize duringthe last 15 seconds of the Water Purge. If set at 15 or 30seconds the water inlet valve will not energize during theharvest water purge.15SV16176-50 Part No. 80-1100-3