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THEORY OF OPERATION

3-5

OPERATIONAL MODES

There are four main operational modes for the

ice maker (more detailed operation is found in

the ﬂ ow chart on page 6-5):

• Freeze

• Harvest

• Clean

• Service (Diagnostics)

ICE MAKING CYCLE

In addition, there are two possible “Off” cycles

for the ice maker. They occur when:

1.The bin is full of ice and the LED is il-

luminated “ON/OFF” (Idle mode).

2.The "ON/OFF” button has been

pressed. The ON/OFF LED will go out.

Electrical System

Line Voltage is supplied to the electrical control

switches and the primary side of the step-down

dual transformer. The dual transformer reduces

120 VAC to 9.4 VAC for the cutter grid, 14

VDC for the bin light and 12 VAC for the drain

and recir-culating pumps. The electronic

control board directs 12 VAC to t he water re-

circulating and reservoir drain pumps, and

120 VAC to the hot gas solenoid, condenser

fan motor, water valve, and compressor. An

evaporator thermistor supplies temperature

information to the electronic control to determine

when to terminate the harvest cycle.

Refrigeration System

The hot gas refrigerant, under high pressure, is

forced through the condenser, where it changes

into a liquid, and ﬂ ows through the drier and

capillary tube into the evaporator. Under low

pressure in the evaporator, the liquid refrigerant

absorbs heat from the water ﬂ owing over the

evaporator as the refrigerant evaporates into

a gas. As a

low pressure gas, the

refrigerant

ﬂ ows back through the suction line of the heat

exchanger, to the compressor.

During the Freeze mode, some of the hot gas

that is in the condenser accumulating tube,

condenses to a liquid, and remains in the ac-

cumulating tube.

During the later stages of the Freeze mode, as

the ice slab forms on the evaporator freezing

plate, some of the refrigerant passing through

the evaporator will not evaporate into a gas, but

will remain a liquid. This liquid refrigerant will

settle in the accumulator, while the refrigerant

vapor is sucked off through the suction tube at

the top of the accumulator. This accumulated

liquid refrigerant will eventually be directed to

the evaporator to quickly warm the evaporator

plate during the Harvest mode.

NOTE: It is very important that the accumulator

is not tilted out of a horizontal position. If moved,

it could cause compressor failure.

Water System

The water recirculating pump moves the water

from the reservoir pan up to the distributor,

where it ﬂ ows out over the evaporator freez-

ing plate.

Water that does not freeze on the evaporator

plate runs off the front edge, and falls back into

the reservoir, where it is recirculated back to

the water distributor.

As the ice slab forms, the minerals in the water

are on the

surface of the ice. The water ﬂ ow-

ing over the top of the ice slab washes these

minerals back into the water

reservoir pan.

The

water continues to recirculate until the water

level in the reservoir drops to the bottom of the

water level sensor. When the water level in the

reservoir drops below the sensor, the control

terminates the freeze mode and initiates the

harvest mode.

The control signals the water valve to fill to the

selected water level setting. The touch sensor

is used to accurately fill to the correct volume.

Depending on the ice thickness setting the fill

level is calculated by the amount of time it

takes the water to reach the touch sensor with

a max time of 3 min. Thin Ice uses 35 ounces

(1035cc), Normal Ice 38.9 ounces (1153cc),

and Thick Ice 40.9 ounces (1212cc).

Operating Systems (Cont.)