Thermo King UT-1200, Manual

Page: 46 / 169

Operating Instructions for Standard HMI Control Panel
46
IMPORTANT: During the defrost cycle, the box
temperature will rise toward 50 F (10 C). This is
normal and is caused by the defrost cycle
warming the evaporator coil. Since the damper
door is closed during the defrost cycle, this warm
air is not allowed to pass into the truck box.
Figure 29: Box temperature will rise toward
50 F (10 C)
Terminating a Defrost Cycle
The defrost cycle terminates automatically when
the coil temperature is greater than or equal to 52
F (11 C) or the maximum defrost timer expires.
Alarm code 14, Defrost Terminated by Time, will
generate if the maximum defrost time is exceeded.
When the defrost cycle is completed the amber
LED next to the DEFROST Key will turn off.
Defrost can also be terminated by turning the unit
off and back on.
Alarms
Alarm Code Notification
If an alarm condition occurs, the Alarm Icon will
appear on the display. If the alarm is a Check
Alarm, the Alarm Icon will turn on but the unit
will continue to run. If the alarm is a Shutdown
Alarm, the Alarm Icon and the display will flash
on and off and the unit will shut down.
.
Figure 30: Alarm Icon
Displaying Alarm Codes
Alarms are displayed by simultaneously pressing
and holding the ON Key and PRETRIP TEST
Key. The alarm display will appear as shown
below. The upper display shown in Figure 31
indicates that Alarm Code 127 Setpoint Not
Entered has been set. The lower display indicates
that only one alarm code exists.
Figure 31: ON and PRETRIP TEST Keys
If more than one alarm code has been set, they are
displayed with the most recent alarm shown first.
Use the UP ARROW Key to scroll through the
alarms.
Clearing Alarm Codes
After the alarm situation is resolved, press the
ENTER Key to clear the alarm code currently
being shown. When all alarms have been cleared
the display will show all zeros to indicate that no
alarm codes exist.
Figure 32: ENTER Key
The display will return to the Standard Display
about 30 seconds after all alarms have been
cleared.
Figure 33: Standard Display
Important Alarm Notes
• All alarms must be viewed before any of the
alarms can be cleared.
• If an alarm will not clear, it may still exist. If
the alarm is not corrected, it will not clear or
may be immediately set again.