Sub-Zero UC-24 series Service Manual page 12

Electronic Control System
Regulate Freezer Zone Temperature (UC-24C Only)
When the freezer compartment thermistor detects high off-set temperature, calling for cooling, the compressor and
condenser fan motor are energized, as well as the evaporator fan motor. (See Figure 3-18)
If the door is opened while the evaporator fan is operating, the microprocessor will detect the power signal to the
lights and cut power to the fan.
NOTES:
• When the freezer compartment calls for cooling after a defrost, the evaporator fan will not be allowed to run until
the thermistor on the evaporator drops to 35°F (2°C).
• If compartment tem-
perature exceeds
either high or low
offset the tempera-
ture display will
change by one
degree (1°) per
minute.
• If freezer compart-
ment thermistor is
faulty, compressor
operation defaults to
twenty (20) minutes
ON, twenty (20) min-
utes OFF cycling;
EE appears in left of
LCD; SERVICE
flashes and Error
Code 07 is logged.
• If evaporator ther-
mistor is faulty, the
compressor will be
energized after the
dwell time and the
evaporator fan will
be energized 3 min-
utes later; SERVICE
flashes and Error
Code 08 is logged.
• When in Sabbath
Mode, the freezer
compartment ther-
mistor still controls
compressor opera-
tion, except there is
a random fifteen
(15) to twenty-five
(25) second delay
before the compres-
sor is energized.
#7003933 - Revision B - November, 2007
LOW VOLTAGE SCHEMATIC
MEMBRANE KEYPAD
DISPLAY
PIN 1
DISPLAY BOARD
THERMISTOR CABINET/FREEZER
1. Freezer compartment thermistor at high off-set temp. calling for cooling.
HIGH VOLTAGE SCHEMATIC
ORANGE
GRAY/WHITE
J2
P4
PIN 1
P3
MAIN BOARD
P1
P2
PIN 1
J6
J4
PIN 1
PIN 1
PIN 1
J3
J5
ORANGE
Figure 3-18. UC-24C Signal Trace - Regulate Freezer Zone Temperature
Under Counter (UC-24) Series
REF AIR DUCT BAFFLE
YELLOW W/WHITE STRIPE
YELLOW W/BLACK STRIPE
YELLOW W/RED STRIPE
J2
PIN 1
J3
THERMISTOR
ORANGE W/RED STRIPE
EVAPORATOR
BLUE W/WHITE STRIPE
BLUE W/WHITE STRIPE
BLUE W/BLACK STRIPE
BLUE W/BLACK STRIPE
THERMISTOR CABINET/REF
115 VOLTS
60 CYCLES
L1 NEUTRAL
WHITE
2. Compressor and con-
denser fan energized.
WHITE
BLACK
PURPLE
BLUE
GRAY/WHITE
RED
ORANGE
REF LIGHT SWITCH
3. Door is closed, so no power to lights.
This is monitored via the orange wire.
THERMAL
ICEMAKER
FUSE
BLACK
3-12
J6
ORANGE
YELLOW J4
RED
WHITE
BLUE W/RED STRIPE
J5
OVERLOAD
PROTECTOR
COMPRESSOR
M
M
REF FAN MOTOR
CONDENSER FAN
M
DEFROST HEATER
R55 OHMS
4. Evap fan
energized.
REF (TOP) LIGHT
WHITE
ICEMAKER
VALVE
TAN
R160 OHMS
J2
P4
PIN 1
P3
MAIN BOARD
P1
P2
PIN 1
PIN 1
PIN 1
PIN 1
J3
WHITE
RUNNING
CAPACITOR
(WHEN
USED)
COMPRESSOR
STARTING
RELAY
WHITE
WHITE
WHITE
WHITE
WHITE
WHITE