Sub-Zero UC-24 series

Electronic Control System
Under Counter (UC-24) Series
3-15
#7003933 - Revision B - November, 2007
Minimize Condensation on Refrigerator Door Glass (UC-24B Only)
To help minimize the formation of condensation, or fog, on the door glass of the model UC-24B, the microprocessor
detects when the refrigerator door is opened, via the light switch, then when the door closes, the evaporator fan is
energized for five (5) minutes, regardless of compressor operational state. This draws any warmer moist air away
from the door glass. (See Figure 3-21)
NOTE: The evaporator fan also cycles with the compressor.
Figure 3-21. UC-24B Signal Trace Schematic - Evaporator Fan Operation in Glass Door Unit
RELAY
STARTING
(WHEN
USED)
CAPACITOR
COMPRESSOR
REF LIGHT
SWITCH
WHITE
BLACK
PROTECTOR
M
M
M
ORANGE
PURPLE
ORANGE
PIN 1
PIN 1
PIN 1
YELLOW
MAIN BOARD
PIN 1
ORANGE
PIN 1
WHITE
REF (TOP)
LIGHT
REF FAN MOTOR
OVERLOAD
CONDENSER FAN
RED
COMPRESSOR
RUNNING
WHITE
NEUTRAL
HIGH VOLTAGE SCHEMATIC
L1
115 VOLTS
60 CYCLES
LIGHTS
PINK
WHITE
REF LIGHT SWITCH
LIGHT TUBE SWITCH
(UC-24B ONLY)
J4
J5
J3
J6
J2
P3
P2
P1
P4
2. Evap fan energized
for 5 minutes.
1. Door is opened, then closed. This is
monitored via the orange wire.