Frigidaire LGUB2642LF2, Service Manual

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4-3
About Ice Cube Production
There is a thermistor located inside a foam insulation cover under the ice maker flex tray that senses the temperature
of the water and the ice tray. The signal from the thermistor is sent to the lower control board of the refrigerator. The
thermistor looks for the water in the tray to drop to a point that the water is changing from a liquid to a solid in the
freezing process. It then looks for the temperature of the cubes to drop another 13 degrees F, at this point the lower
control board will start the ice maker drive motor. The drive motor will start to turn the flex tray CCW to about 40
degrees and start to drop the bail arm down. If the bail arm does not hit ice in the bucket (and therefore does not close
the internal switch), the drive motor will continue to rotate the tray CCW allowing the end of the tray opposite the drive
motor to contact a stop on the ice maker frame. The motor will continue to drive the front end of the tray, twisting it,
and breaking the cubes free to fall into the ice bucket. The motor will continue to drive the tray CCW until the tab inside
the gearbox closes the internal switch. At this point, the motor will reverse and rotate the tray CW back to the home
(horizontal) position. During the twisting process, the bail arm will be dropped and raised twice –once during the CCW
rotation and once during the CW rotation. Once the tray is back to the home position, the water valve will immediately be
activated to fill the tray with water. If the bail arm hits ice in the bucket (and closes the internal switch), then the motor
will immediately reverse and bring the tray back to the home position. At this point, the ice maker will enter “full bucket”
mode. It will simply sit and wait for ice to either be dispensed or a fresh food door to be opened (user possibly removing
ice manually from the ice bucket). About 1 minute after either event, the tray will rotate and drop the bail arm to check
the ice level. If it detects ice, then it will reverse and re-enter full bucket mode. If it does not detect ice, then it will twist
and dump the new ice into the bucket, go back to the home position, fill with water, and start the ice making process
over again.
Figure 4-7. Ice Maker Refrigeration Flow Schematic
Ice Maker (Flex Tray Fresh Food Compartment)
Ice Mak er Chamber
Ev aporator
Unit Ev aporator
Capilla ry Tu be
Suction Line
Va riable
Compressor
Condenser
Drier
Heat
Exshanger
Suction Line
Jumper Tube From Ice Maker Evaporaotr To Unit Evaporator
Ice Size Selection (for service use only)
There are 3 settings for the water fill time. Settings 1,
2, and 3 correspond to 4.6 sec, 5.8 sec, and 7.0 sec
respectively. The proper fill amount for this ice maker
is 75 to 105 ml (2.5 to 3.5 oz). For this ice maker, the
purpose of the variable fill size is to be able to get
the proper amount of water in the tray so that the
ice maker can operate correctly across a wide range
of water supply pressures. It is not intended for the
purpose of making larger or smaller cubes.
The default setting is size 1 (4.6 sec). This setting is
intended for normal supply pressure of 45 –50 psi and
higher, and should be fine for most installations. If the
pressure is below 40 -45 psi, but higher than 25 –30
psi, then setting 2 (5.8 sec) is recommended. If the
pressure is below 25 –30 psi, then setting 3 (7.0 sec) is
recommended.
Setting 3 should not be used for higher pressures (70+
psi) because of the risk of overflowing the ice maker.
The excess water will spill onto the existing ice in the
bin and cause it to clump together.
To change the fill size setting, press the CUBE button
twice within two seconds. The FZ display will show ICE,
and the FF display will show 1, 2, or 3 horizontal bars
corresponding to the current fill size. Use the FF Up and
Down buttons to change to the desired fill size. Press
CUBE again to save the setting.