Carrier 69NT40-561-399 Operation And Service Manual page 94

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CODE TITLE
P9-0 DTT Closed and
Open Test
P10 Tests - Frozen Mode Tests:.
CODE TITLE
P10-0 Frozen Mode Heat
Test
P10-1 Frozen Mode Pull-
down Test
P10-2 Frozen
Maintain Tempera-
ture Test
T-365
DESCRIPTION
P9-0 DTT Closed and Open Test
During P9-0 the defrost temperature sensor (DTS) reading will be displayed
on the left display. The right display will show the supply air temperature.
The unit will run FULL COOL for 30 minutes maximum until the DTT is con-
sidered closed. This step may not have to be executed. Once the DTT is con-
sidered closed, the unit simulates defrost by running the heaters for up to two
hours, or until the DTT is considered open.
Test fails if:
The DTT is not considered closed after the 30 minutes of full cooling
HTT opens when DTT is considered closed or if return air temperature rises
above 248°C (120°F).
Test passes if the DTT is considered open within the 2 hour heat cycle time
limit.
DESCRIPTION
If the container temperature is below 7.2°C, the setpoint is changed to 7.2°C.,
and a 180 Minute timer is started. The control will then be placed in the equiv-
alent of normal heating. If the container temperature is above 7.2°C. at the
start of the test, then the test proceeds immediately to test 10-1. During this
test, the control temperature will be shown on the right display.
The test fails if the 180 Minute timer expires before the control temperature
reaches setpoint - 0.3°C. If the test fails, it will not auto-repeat. There is no
pass display for this test. Once the control temperature reaches setpoint, the
test proceeds to test 10-1.
Control temperature must be at least 7.2°C (45°F) The setpoint is changed
to -17.8°C. The system will then attempt to pull down the control temperature
to setpoint using normal frozen mode cooling. During this test, the control
temperature will be shown on the right display.
The test passes if the control temperature reaches setpoint minus 0.3°C be-
fore the 180 minute timer expires. Otherwise, the test fails. Upon failure and
when initiated by an automatic Pre-trip sequence, P10-1 will auto-repeat
once by starting P10-0 over again.
Mode Test P10-1 must pass for this test to execute.
Same as for test 8-2 except the control temperature is the return probe tem-
perature.
The average error must be +/-1.6°C. If the DataCORDER supply tempera-
ture probe is invalid, the test fails and the control probe temperature will be
recorded as -50°C. Upon failure and when initiated by an automatic Pre-trip
sequence, P10-2 will auto-repeat by starting P10-0 over again.
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