3
minimum of 20 seconds have elasped. If
necessary, the heater will cycle with a turn on
temperature of 32°F (0°C) and a turn off
temperature of 35.6°F (2°C)
To insure the motor completes a full
revolution, the control checks to see the motor
is “not home” for at least 10 seconds and the
feeler arm is “in” for at least 10 seconds. Once
these two conditions are met and the motor
reaches home position, the harvest cycle will
be complete and the motor will turn off.
The harvest cycle consists of one
complete revolution of the ejector to sweep the
cubes from the mold and drop them into the
ice bucket. If the harvest cycle is not complete
within 7 minutes, the control will assume that a
cube is blocking the completion of a cycle and
will initiate a harvest fix mode. If the harvest
cycle is not complete within 30 minutes, the
control will assume some other problem has
occurred and will enter the fault mode.
Harvest Fix
If the harvest cycle is not complete
within 7 minutes, the control will enter a “Harvest
Fix” mode. In the harvest fix mode, the
temperature of the mold will be raised in an
attempt to melt any cubes that are jammed. The
control will turn the heater off when the
thermistor temperature reaches 68°F (20°C)
and turn it back on again at 59°F (15°C). During
this time, the motor will be cycled off for 10
seconds of every minute. If the motor reaches
the home position, a second revolution of the
ejector will occur to verify there is no more
blockage. When the second revolution is
complete, the control will enter the freeze cycle
without allowing a water fill to insure against a
double shot of water. The control will enter a
Fault Mode if a harvest cycle (including harvest
fix) is not complete within 30 minutes. Potential
causes for a harvest to take longer than 30
minutes are:
•
Stuck ejector - caused by a cube that was
not cleared or a mechanical problem
•
Bad heater - caused by the heater, control
board or thermal cutout (TCO)
•
Bad motor - caused by motor or control
board
•
Motor home position not operating - caused
by control board or loose magnet - the result
will be continuous ejector operation
•
Thermistor - open or shorted
THERMISTOR
˚F
˚C
-40
-40
35.6
2
39.2
4
50
10
59
15
68
20
77
25
10K
176
80
207K
25.37K
23.27K
18.07K
14.75K
12.11K
1.67K
Water Fill
When harvest is complete, the icemaker
will enter the “Water Fill” cycle. The amount of
water entering the mold is controlled by
temperature. Before any water enters, the mold
must reach a temperature of 35.6°F (2°C). This
“prechilling” of the mold allows the thermistor
to better detect the level of the water. Water
entering the icemaker will cause the mold
temperature to change, effecting the resistance
of the thermistor.
The icemaker thermistor has a negative
coefficient. That is, an increase in temperature
will cause a decrease in resistance. The chart
below shows the most common values used
by the electronic control.
Once the mold has completed harvest
and cooled to 35.6°F (2°C), a first fill will be
initiated. This first fill activates the water valve
for 5.1 seconds. After this fill, there will be a 15
second delay before determining if the icemaker
is sufficiently full. If the temperature exceeds
39.2°F (4°C) after the 15 second delay, the
icemaker will end the water fill cycle and start
Summary of Contents for Electronic Icemaker
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