Manitowoc Manitowoc NEO UDF0190A, Installation, Operation And Maintenance Manual

14 

Part Number:040005890 Rev 06  11/20

Operation 

Section 3

Ice Making Sequence of Operation

NOTE: The On/Off button must be depressed and the ice 

damper must be closed before the ice machine will start.

Water Purge Cycle

The ice machine purges any remaining water from the 

water trough down the drain.

Freeze Cycle

Prechill - The refrigeration system chills the evaporator 

before water flow over the evaporator starts. The water inlet 

valve energizes during the pre-chill and remains on until 

the ice thickness float switch is satisfied.
Freeze - With water trough thermistor , the following 

sequence occurs in the frezze cycle:
•  When the water temperature reaches 34°F, the water 

pump will de-energize for 25 seconds, then re-

energizes.

•  When the water pump restarts the water inlet solenoid 

energizes for 7 seconds.

•  Water flowing across the evaporator will start to freeze 

and build ice on the evaporator. After a sheet of ice 

has formed, the harvest float switch signals the control 

board to start a harvest cycle.

Freeze - Without water trough thermistor , the following 

sequence occurs in the frezze cycle:
•  At 3.75 minutes the water pump de-energizes for 25 

seconds , then re-energizes.

•  When the water pump restarts the water inlet solenoid 

energizes for 7 seconds.

•  Water flowing across the evaporator will start to freeze 

and build ice on the evaporator. After a sheet of ice 

has formed, the harvest float switch signals the control 

board to start a harvest cycle. 

Harvest Cycle

Any remaining water is purged down the drain as 

refrigerant gas warms the evaporator. When the evaporator 

warms, the sheet of cubes slides off the evaporator and into 

the storage bin. If all cubes fall clear of the ice damper, the 

ice machine starts another freeze cycle.

Full Bin Cycle

If the ice damper is held open by ice cubes, the ice machine 

shuts off. When the ice damper closes, the ice machine 

starts a new cycle at the water purge.

Control Board Timers

The control board has the following non-adjustable timers:
•  The ice machine is locked into the freeze cycle for 6 

minutes before a harvest cycle can be initiated.

•  The maximum freeze time is 45 minutes, at which time 

the control board automatically initiates a harvest 

sequence.

•  The maximum harvest time is 7 minutes. When harvest 

is complete the control board automatically initiates a 

freeze sequence.

•  If the ice damper does not open and close within 

the 7 minute harvest cycle, the ice machine enters 

a water thaw cycle for 170 seconds. If the damper 

does not open and close within the 170 second thaw 

cycle, a second thaw cycle starts. The control board 

automatically initiates a freeze sequence when the thaw 

cycle(s) is complete.