Observe Unit Operation; Probe Diagnostic Logic - Carrier 69NT40-561-019 Operation And Service Manual

a. Press the PRE-TRIP key. This accesses a test selection menu.
b. TO RUN AN AUTOMATIC TEST: Scroll through the selections by pressing the UP ARROW or DOWN
ARROW keys to display AUTO, AUTO 1, AUTO 2, or AUTO 3 as desired, then press the ENTER key.
1. The unit will execute the series of tests without any need for direct user interface. These tests vary in
length, depending on the component under test.
2. While tests are running, "P#-#" will appear on the left display; the #'s indicate the test number and sub-
test. The right display will show a countdown time in minutes and seconds, indicating the amount of time
remaining in the test.
When a failure occurs during automatic testing, the unit will suspend operation awaiting oper-
ator intervention.
When an automatic test fails, it will be repeated once. A repeated test failure will cause "FAIL" to be shown on the
right display, with the corresponding test number to the left. The user may then press the DOWN ARROW to repeat
the test, the UP ARROW to skip to the next test or the PRE-TRIP key to terminate testing. The unit will wait indefi-
nitely or until the user manually enters a command.
When Pre-Trip test Auto 2 runs to completion without being interrupted, the unit will terminate
pre-trip and display "Auto 2" "end." The unit will suspend operation until the user depresses
the ENTER key!
When an Auto 1 runs to completion without a failure, the unit will exit the pre-trip mode and return to normal control
operation. However, dehumidification and bulb mode must be reactivated manually if required.
c. TO RUN AN INDIVIDUAL TEST: Scroll through the selections by pressing the UP ARROW or DOWN
ARROW keys to display an individual test code. Pressing ENTER when the desired test code is displayed.
1. Individually selected tests, other than the LED/Display test, will perform the operations necessary to ver-
ify the operation of the component. At the conclusion, PASS or FAIL will be displayed. This message will
remain displayed for up to three minutes, during which time a user may select another test. If the three
minute time period expires, the unit will terminate pre-trip and return to control mode operation.
2. While the tests are being executed, the user may terminate the pre-trip diagnostics by pressing and
holding the PRE-TRIP key. The unit will then resume normal operation. If the user decides to terminate a
test but remain at the test selection menu, the user may press the UP ARROW key. When this is done,
all test outputs will be de-energized and the test selection menu will be displayed.
3. Throughout the duration of any pre-trip test (except the P-7 high pressure switch tests), the current and
pressure limiting processes are active. The current limiting process only is active for P-7.
d. Pre-Trip Test Results
At the end of the pre-trip test selection menu, the message "P," "rSLts" (pre-trip results) will be displayed.
Pressing the ENTER key will allow the user to see the results for all sub-tests (i.e., 1-0, 1-1, etc). The
results will be displayed as "PASS" or "FAIL" for all the tests run to completion since power up. If a test has
not been run since power up, "-----" will be displayed. Once all pre-test activity is completed, dehumidifica-
tion and bulb mode must be reactivated manually if required.
5.8

OBSERVE UNIT OPERATION

5.8.1

Probe Diagnostic Logic

For units configured with four temperature probes, which include the supply and return temperature probes and the
supply and return DataCORDER probes, the controller continuously performs probe diagnosis testing that com-
pares the four probes. If the diagnosis result indicates a problem exists, the controller will perform a probe check to
identify which probe or probes are in error.
CAUTION
!
CAUTION
!
5–5 T-359