Functions Of Model 427R-2 Ref. Section Electronic Control System; Display Zone Temperatures; High Voltage - Sub-Zero 424HAG/O-2 Service Manual

Wine Storage
Wine Storage

FUNCTIONS OF MODEL 427R-2 REF. SECTION ELECTRONIC CONTROL SYSTEM

The following few pages explain monitoring, regulating and controlling functions of the electronic control system.

Display Zone Temperatures

Temperature signals from the compartment thermistor are monitored by the microprocessor, then displayed on the
LCD. Though the zone air temperature fluctuates, average temperature is displayed (See Figure 3-54).
NOTE: If zone temperature changes, temperature display will change by one (1) degree per minute.
Supply Power to the Lighting System
Power is supplied to the lighting system through the control board when the unit is switched ON by pressing the
UNIT ON/OFF key. With a drawer open, the light switch allows power to the lights. (See Figure 3-55).
NOTE: Power to the lights is monitored by the microprocessor to control the door ajar alarm feature and to help
control the operation of the evaporator fan.
NOTE: When in Sabbath Mode, the lighting system is disabled. Sabbath Mode will be covered later.

HIGH VOLTAGE

ORANGE
J2
J6
MAIN
J4
BOARD
J5
Figure 3-55. Signal Trace Schematic (High Voltage) of Lighting System
(400-
(400-
Average temperature displayed
Figure 3-54. Display Zone Temperatures
2. Switch position monitored for
alarm and fan operation.
NEUTRAL WHITE
WHITE
P4
BLACK
BLACK
PURPLE
P3
1. 115 Volts sup-
PURPLE
plied to light
P1
BLUE
system unless
P2
OFF, or in
Sabbath Mode.
RED
J3
6 5 4
1 3
DPDT RELAY
NEUTRAL WHITE
ORANGE
Series
Series
2
2
)
)
REFRIGERATOR
COLDER
L1 NEUT
115 VOLTS
60 CYCLES
OVERLOAD
PROTECTOR
RED
DOOR SWITCH
YELLOW
DOOR SWITCH
ORANGE
3-29
Electronic Control System
UNIT
WARMER
ON/OFF
ON/OFF
NEUTRAL WHITE
CONDENSER FAN MOTOR
M
2000 Ω
MULLION HEATER
COMPRESSOR
STARTING RELAY
M
COMPRESSOR
EVAPORATOR FAN MOTOR
M
TOP DRAWER LIGHTS
LOWER DRAWER LIGHTS
#3758410 - Revision C - May, 2014