Sub-Zero UC-24 series Service Manual page 44

Troubleshooting Guides
PROBLEM
H. Warm Freezer Temperatures,
"SERVICE" not displayed or
Flashing
#7003933 - Revision B - November, 2007
Under Counter (UC-24) Series
POSSIBLE CAUSE
No Power to Unit
Unit Switched OFF
Unit in Show Room Mode
Control Set Too High
Warm Food Load
High Room Ambient
Door Ajar
a. Food Product Obstruction
b. Door Closer Defective
Condenser Air Flow
a. Dirty condenser
b. Condenser fan blade obstructed, loose,
or defective
c. Condenser fan motor disconnected
d. Condenser fan motor defective
Faulty Light Switch
Evaporator Fan Fault
a. Fan blade obstructed or out of position
b. Evaporator fan motor disconnected
c. Power to Fan Fault, or Fan Motor
Defective
(NOTE: Compressor must be running)
Compartment Thermistor Misread
8-10
TEST / ACTION
Check power to unit, plug unit in or switch
supply circuit breaker ON.
Check for "OFF" displayed at LCD. If off,
press POWER key.
Press POWER key to OFF, then press and
hold WARMER& COLDER keys, and press
POWER key.
Check set-point. If high, adjust.
Check contents of freezer for warm food
load. Instruct customer.
Instruct customer unit performs best
between 60°F(16°C) and 90°F(32°C).
a. Move obstruction.
b. Replace door closer.
a. Clean condenser.
b. Remove obstruction, or tighten blade, or
replace if defective.
c. Check continuity from motor to compressor.
Reconnect / repair wiring or connections.
d. Check for AC Voltage to motor, replace if
defective.
Check operation of light switch, lights off
when switch is depressed. Replace switch if
defective.
a. Move obstruction or reposition blade.
b. Check electrical connections & continuity
from control board to motor. Reconnect /
repair bad connections.
c. With light switch depressed, check for AC
Voltage from control board to fan motor.
Replace control board if defective, or
Replace motor if defective.
Check resistance of freezer compartment
thermistor for 30,000 to 33,000 ohms at
32°F (0°C). Replace if defective.