Sub-Zero Built-In Series Assembly page 25

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Electronic Control System
Monitor, Regulate and Display Freezer Compartment Temperatures
Temperature signals from the freezer compartment thermistor are monitored by the microprocessor. When the
freezer compartment thermistor detects high offset temperature, calling for cooling, the freezer compressor is cycled
ON and in most cases the evaporator fan motor receives a high-speed run command, switching it ON. However, if
the freezer is calling for cooling following a defrost, the evaporator fan will not be switched ON until the freezer evap-
orator falls to 35°F (2°C). When the compartment reaches low offset temperature, the compressor and evaporator
fan are switched OFF. Though compartment air temperature fluctuates from OFF and ON cycles, it is the freezer
compartment's "average" tem-
perature that is displayed at the
left side of the LCD. (See
Figure 3-44)
NOTES:
• Freezer zone temperature
range is -5°F (-21°C) to +5°F
(-15°C)
• If average compartment tem-
perature changes, the display
will change by one degree
per minute.
• When high offset is detected
after a defrost, the freezer
compressor will not be ener-
gized until after the five (5)
minute time delay/dwell that
follows all freezer defrosts.
• If a freezer compartment
thermistor is faulty, the freez-
er compressor defaults to 20
minutes ON, 20 minutes OFF
cycling, EE appears at left in
LCD, the service icon flashes
and the appropriate fault
code is logged.
• If a freezer evaporator ther-
mistor is faulty, the freezer
compressor will be energized
immediately after the five (5)
minute dwell and the evapo-
rator fan motor will be ener-
gized three (3) minutes later,
the service icon flashes and
the appropriate fault code is
logged.
• If in Sabbath Mode, the com-
partment thermistor still
controls compressor oper-
ation, except that when
high offset is reached,
there is a random 15 to 25
second delay before the com-
pressor is energized.
• The condenser fan is ener-
gized whenever a compres-
sor is energized.
#7019014 - Revision A - October, 2010
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Main Menu
Built-In (BI) Series
Built-In (BI) Series
HIGH VOLTAGE
BLACK
WATER FILTER SWITCH
N.O.
NEUTRAL
L1
L1
MAIN LIGHTS
COMP1
COMP2
DEFROST HTR
MAIN
CONTROL
BOARD
LOW VOLTAGE
NEUTRAL
L1
L1
MAIN LIGHTS
COMP1
COMP2
DEFROST HTR
Average temp.
displayed at
Left of LCD
EXERNAL
DEVICE
KEYPAD
Figure 3-44. Signal Trace Schematic: Regulating Freezer Temperature
Main Menu Built-In Series Menu
Built-In Series Menu
L1
115 VOLTS
NEUTRAL
60 CYCLES
3. Condenser fan
energized
WHITE/BLUE
FZ DOOR SWITCH
N.C.
YELLOW YELLOW
N.C.
YELLOW BROWN
REF DOOR SWITCH
ORANGE/BLACK
ORANGE
WHITE/BLUE
GRAY/WHITE
BLUE
DEFROST TERMINATOR
2. Compressor energized
5. Run command
1
WHITE/BLACK
17
FLOW
BLACK/WHITE
THERMISTER FREEZER EVAP
BROWN METER
BLUE
BROWN
THERMISTER FREEZER CABINET
BLUE
1
BROWN
16
1. Freezer's high offset temperature detected
3-26
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WHITE
ISOLATION VALVE
660 Ω
WATER VALVE
TAN/WHITE
TAN
160 Ω
PINK IM
CONDENSER FAN MOTOR
M
WHITE/RED
RED/WHITE
AIR FILTER LIGHT
FREEZER LIGHTS
ORANGE/BLACK
ORANGE
REF LIGHTS
CRISPER LIGHTS
FILL-TUBE HEATER
2300-2900 Ω
DEF HEATER
27.9-30.9 Ω
REFRIGERATOR COMPRESSOR
STARTING RELAY
GRAY
FREEZER COMPRESSOR
STARTING RELAY
PURPLE
sent to evapo-
rator fan
RED
BLUE/WHITE
M
YELLOW/BROWN
YELLOW
BLUE
WHITE
4. Freezer evapo-
rator below
35°F (2°C)
THERMISTER REF EVAP
BLUE
BROWN
THERMISTER REF CABINET
BLUE
BROWN
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE
M
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