Wolf Sub-Zero ICB400 Series Service Manual page 24

International W
International W
Control Compressor, Condenser Fan, Dual Refrigerant Valve and Evaporator Fan Motors
The control senses evaporator and compartment temperatures via thermistors; one on each evaporator, and one in
each compartment. High Offset (Cut-in) is governed by the evaporator temperatures. Low Offset (Cut-out) is gov-
erned by the compartment temperatures. High Offset and Low Offset are based on the set-point.
If either evaporator calls for cooling (evaporator temperature at high offset), power is supplied to the compressor and
condenser fan motor, cycling them ON. The corresponding evaporator fan relay supplies power to the appropriate
evaporator fan switch, cycling the fan ON. Then, two relays on the control board are used to control the dual refrig-
erant valve. The relays are in series with one another. The first "pulse" relay controls the length of time the solenoid
is energized (500ms / 30 pulses per 1/2 second). The second "sign" relay controls the negative polarity, or positive
polarity of the pulse supplied to the valve's solenoid (determined by which evaporator is calling for cooling, ( + ) =
Upper Evaporator, ( - ) = Lower Evaporator). So, when an evaporator calls for cooling, the bead inside of the T-con-
nection of the refrigerant valve is forced to one side or the other, depending on the polarity of the pulse, supplying
refrigerant to the appropriate evaporator
NOTE: If neither compartment is calling for cooling, the compressor and condenser fan are switched OFF.
NOTE: Evaporator fans are switched OFF when the door is open and disabled if the unit is in Showroom Mode.
NOTE: When in Sabbath Mode, evaporator thermistors still control energizing of the compressor and evaporator
fans, except
there is a ran-
dom fifteen
(15) to twenty-
five (25) sec-
ond delay
before power
is supplied to
components.
CONTROL
BOARD
DISPLAY
Figure 3-17. Cooling Signal Trace (Upper Evaporator at High-Offset Temperature, Calling for Cooling)
ine Storage
ine Storage
(See Figure 3-17).
L1 NEUT
230 VOLTS
50/60 CYCLES
J1 1
J8 J2
8
1
2
WINE
BLUE
J3
PINK
14
E2
E1
E3
BLACK
LOW VOLTAGE
MEMBRANE SWITCH
J1
J8 J2
1
2
WINE
J3
CONTROL
BOARD
14
Series
Series
(ICB400)
(ICB400)
WHITE
ORANGE
N.C.
BROWN ORANGE
PINK PINK
N.O.
BLUE BLUE
N.O.
TAN
OVERLOAD PROTECTOR
GRAY
WHITE
1
BLUE W/WHITE
BLUE W/WHITE
BLUE W/BLACK
BLUE W/BLACK
BLUE W/RED
ORANGE W/RED
BLUE W/YELLOW
ORANGE W/YELLOW
8
WHITE W/RED
WHITE W/BLUE
GRAY W/WHITE
E2
E1
E3
3-11
Electronic Control System
LIGHTS
LIGHTS
UPPER
M
EVAPORATOR FAN MOTORS
LOWER
M
AWECO REF VALVE
680 Ω
CONDENSER FAN MOTOR
M
COMPRESSOR
STARTING RELAY
M
COMPRESSOR
3. Energized
THERMISTER 1
LOWER CABINET
THERMISTER 2
UPPER CABINET
THERMISTER 3
LOWER EVAPORATOR
THERMISTER 4
UPPER EVAPORATOR
1. Temperature at
high offset,
Calling for
cooling
7011544 - Revision A - November, 2008
4. Energized
5. 230VAC
pulse, (+
polarity) sup-
plied to sole-
noid, valve
opens supply-
ing refrigerant
to upper evap-
orator
2. Temperature
above low
offset