Carrier 69NT40-561-019, Operation And Service Manual

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T-359 4–14
4.5 CONTROLLER ALARMS
Alarm display is an independent controller software function. If an operating parameter is outside of expected
range or a component does not return the correct signals back to the controller, an alarm is generated. A listing of
the alarms is provided in
Table 4–6 .
The alarm philosophy balances the protection of the refrigeration unit and that of the refrigerated cargo. The action
taken when an error is detected always considers the survival of the cargo. Rechecks are made to confirm that an
error actually exists.
Some alarms requiring compressor shutdown have time delays before and after to try to keep the compressor on
line. An example is alarm code “LO”, (low main voltage), when a voltage drop of over 25% occurs, an indication is
given on the display, but the unit will continue to run.
When an Alarm Occurs:
a. The red alarm light will illuminate for alarm code numbers 15, 17, 20, 21, 22, 23, 24, 25, 26, and 27.
b. If a detectable problem exists, its alarm code will be alternately displayed with the set point on the left display.
c. The user should scroll through the alarm list to deter mine what alarms exist or have existed. Alarms must
be diagnosed and corrected before Alarm List can be cleared.
To Display Alarm Codes:
a. While in the Default Display mode, press the ALARM LIST key. This accesses the Alarm List Display Mode,
which displays any alarms archived in the alarm queue.
b. The alarm queue stores up to 16 alarms in the sequence in which they occurred. The user may scroll
through the list by depressing an ARROW key.
c. The left display will show “AL##”, where ## is the alarm number sequentially in the queue.
d. The right display will show the actual alarm code. “AA##” will display for an active alarm, where “##” is the
alarm code. Or “IA##” will display for an inactive alarm, See Table 4–6 .
e. “END” is displayed to indicate the end of the alarm list if any alarms are active.
f. “CLEAr” is displayed if all alarms are inactive. The alarm queue may then be cleared by pressing the
ENTER key. The alarm list will clear and “-----” will be displayed.
NOTE
AL26 is active when all of the sensors are not responding. Check the connector at the back of the con-
troller; if it is loose or unplugged, reconnect it, then run a pre-trip test (P5) to clear AL26.
4.6 UNIT PRE-TRIP DIAGNOSTICS
Pre-trip Diagnostics is an independent controller function that suspends normal refrigeration controller activities
and provides preprogrammed test routines. The test routines include Auto Mode testing, which automatically pre-
forms a pre-programmed sequence of tests, or Manual Mode testing, which allows the operator to select and run
any of the individual tests.
CAUTION
!
Pre-trip inspection should not be per formed with critical temperature cargoes in the container.
CAUTION
!
When Pre-trip key is pressed, economy, de humidification and bulb mode will be deactivated. At
the completion of Pre-trip activity, economy, dehumidification and bulb mode must be reactivated.
Testing may be initiated by use of the keypad or via communication, but when initiated by communication the con-
troller will execute the entire battery of tests (auto mode).