Frigidaire LGUB2642LF2, Service Manual

Page: 55 / 187

4-11
About Ice Cube Production
When the temperature of the ice mold goes below 28°F and the bail arm is in the down position, the ice mold heater
will turn on and the EEV will close as long as the unit is not in Freezer Recovery or Sabbath modes, or the 20 minute
delay after defrost or POR. The heater will run until the mold reaches 34°F. Then the motor will move the ice mold
from the left hand freeze position around the fingers of the evaporator to the right hand fill position. At this point
the electronic control will wait for 45 seconds to allow the compressor to continue to pull the remaining refrigerant
from the finger evaporator. Then the control will provide power to the finger heater for 2-1/2 minutes, this will allow
the cubes to slide off the fingers. The harvest heater Bi-metal should open prior to the 2-1/2 minute interval, but
the system will continue to provide power to the open circuit for the entire time. The control will go through several
short internal tests for about 10 seconds. Then the mold will pull away from the fill position and then move back.
This is to verify that the fill position switch is working properly. Now the ice mold will fill with water. The fill time is
4 seconds and will supply approximately 75 cc. of water. The control will now hold the ice mold for an additional 5
seconds to allow all water drops to enter the mold. Next, the drive motor will actuate and move the ice mold back
under the evaporator fingers. The motor will shut off and the EEV will open, allowing for refrigerant flow through the
fingers to start the water freezing process over again.
If the fill switch on the right side does not make connection when the ice mold moves from the freeze position on
the left, to the fill position on the right, the mold heater will come back on for five minutes to melt any ice that may
be obstructing the ice mold. The mold will then attempt to move to the right again. If the switch still cannot be
reached, the IM (Ice Maker) will repeat this process up to five times. If the switch cannot be reached after five tries,
the IM will stop trying for thirty minutes. After thirty minutes, it will try five times again. If the switch still cannot
be reached after the second series of attempts, then the IM will stop trying and change over to its minimum energy
usage mode to cool the compartment and keep any existing ice frozen. The IM will wait in this condition until the
next system defrost has completed, at which point it will repeat the process of trying to reach the fill switch.
If the freeze switch on the left side does not make connection when the ice mold moves from the right fill position to
the left freeze position, the IM will execute the same process as above except it will turn on both the mold and the
finger evaporator heaters.
Figure 4-11. Ice Maker Refrigeration Flow Schematic
Heat Exchanger
Ice Ma ker Ev aporator
Ice Ma ker Chamber
Ev aporator
Elect ric
Expansion Va lve
Unit Ev aporator
Capilla ry Tu be
Accumulato r
Suction Line
Va riable
Compressor
Condenser
Drier
Te e-Va lve
Ice Maker (Finger Evaporator Fresh Food Compartment)