Sub-Zero UC-24 series Service Manual page 20

Electronic Control System
ELECTRONIC CONTROL TROUBLESHOOTING INPUT OPERATIONS
The following few pages explain troubleshooting input operations performed at the control panel. The input opera-
tions described are Diagnostic Mode, Manual Component Activation Mode and Temperature Log Recall.
Diagnostic Mode (a.k.a. Actual Temperature Display Mode)
Initiating Diagnostic Mode allows the Service Technician to observe real-time temperature readings from all thermis-
tors without temperature averaging.
To initiate Diagnostic Mode, the unit must be ON, then press and hold either COLDER key, and press the POWER
key, then release both keys (See Figure 3-32). The left display area will show the real-time temperature of the ther-
mistor, the right display area will show the thermistor location code, and all LCD indicators will illuminate. Pressing
either COLDER key while in Diagnostic Mode will toggle forward (increment) to the next thermistor location (See
Figures 3-33 & 3-34), while pressing either WARMER key will toggle backward (decrement) to the previous thermis-
tor location.
NOTE: If the COLDER and POWER keys are pressed and held for ten (10) seconds, Manual Component Activation
Mode will be initiated (this is covered later in the section).
NOTE: Diagnostic Mode will end twenty (20) seconds after the last key stroke.
Figure 3-32. Initiate Diagnostic Mode - Press and Hold Either COLDER Key, Then POWER Key
Figure 3-33. Toggle Through Temperature Readings - Press Either COLDER Key
Figure 3-34. Toggle Through Temperature Readings - Press Either COLDER Key
Model UC-24B
THERMISTOR LOCATION
Beverage Compartment
Evaporator
#7003933 - Revision B - November, 2007
Under Counter (UC-24) Series
("F" Indicates Freezer Zone/Compartment)
("r" Indicates Refrigerator Zone/Compartment)
("E" Indicates Evaporator)
THERMISTOR LOCATION CODE TABLES
Model UC-24C
CODE THERMISTOR LOCATION
r Freezer Compartment
E Refrigerator Compartment
CODE
F Refrigerator Compartment
r
Evaporator E
3-20
Models UC-24R, UC-24RO
THERMISTOR LOCATION
Evaporator
CODE
r
E