T-296
4-4
ber 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 test-
ing. The unit will wait indefinitely, until the user manu-
ally enters a command.
CAUTION
When Pre--Trip test Auto 2 runs to comple-
tion 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 test runs to completion without a failu-
re, the unit will exit the pre-trip mode, and return to
normal control operation. If configuration variable
CnF42 is set to IN, a datacorder trip start will be en-
tered. If CnF42 is set to OUT, the trip start will not be
entered. 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 dis-
played.
1. Individually selected tests, other than the LED/Dis-
play test, will perform the operations necessary to
verify the operation of the component. At the conclu-
sion, 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 termi-
nate pre-trip and return to control mode operation.
2. While the tests are being executed, the user may ter-
minate the pre-trip diagnostics by pressing and hold-
ing the PRE-TRIP key. The unit will then resume nor-
mal 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 .
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 subtests (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, dehumidification and
bulb mode must be reactivated manually if required.
4.9 OBSERVE UNIT OPERATION
4.9.1 Crankcase Heater
When the crankcase heater is installed, it will be
operational whenever the compressor is off and there is
power to the unit. The heater is connected to a set of
normally closed auxiliary contacts on the compressor
contactor.
4.9.2 Probe Check
If the DataCORDER is off, or in alarm mode the
controller will revert to a four probe configuration which
includes the DataCORDER supply and return air probes
as the secondary controller probes. The controller
continuously performs probe diagnosis testing which
compares the four probes. If the probe diagnosis result
indicates a probe problem exists, the controller will
perform a probe check to identify the probe(s) in error.
a. Probe Diagnostic Logic -- Standard
If the probe check option (controller configuration code
CnF31) is configured for standard, the criteria used for
comparison between the primary and secondary
control
probes is:
1
_
C (1.8
_
F) for perishable set points or 2
_
C (3.6
_
F)
for frozen set points.
If 25 or more of 30 readings taken within a 30 minute
period are outside of the limit, then a defrost is initi-
ated and a probe check is performed.
In this configuration, a probe check will be run as a part
of every normal (time initiated) defrost.
b. Probe Diagnostic Logic -- Special
If the probe check option is configured for special the
above criteria are applicable. A defrost with probe check
will be initiated if 25 of 30 readings or 10 consecutive
readings are outside of the limits
In this configuration, a probe check will not be run as a
part of a normal defrost, but only as a part of a defrost
initiated due to a diagnostic reading outside of the limits.
c.The 30 minute timer will be reset at each of the follow-
ing conditions:
1. At every power up.
2. At the end of every defrost.
3. After every diagnostic check that does not fall out-
side of the limits as outlined above.
d. Probe Check
A defrost cycle probe check is accomplished by
energizing just the evaporator motors for eight minutes
at the end of the normal defrost. At the end of the eight
minute period the probes will be compared to a set of
predetermined limits. The defrost indicator will remain
on throughout this period.
Any probe(s) determined to be outside the limits will
cause the appropriate alarm code(s) to be displayed to
identify which probe(s) needs to be replaced. The P5
Pre-Trip test must be run to inactivate alarms.
4.10 SEQUENCE OF OPERATION
General operation sequences for cooling, heating and
defrost are provided in the following subparagraphs.
Schematic representation of controller action are
provided in Figure 4-3 and Figure 4-4. Refer to Section
3 for detailed descriptions of special events and timers
that are incorporated by the controller in specific modes
of operation.
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