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3
−
39
T-364
7 Controller Pre-trip Test Codes (Sheet 6 of 6)
P9 Test - DTT Close and Open Test:
The DTT in this control is not a physical device, with actual metallic con-
tacts, it is a software function that acts similar to a thermostat. Using various temperature inputs, the DTT func-
tion determines whether a thermostat mounted on the Evaporator Coil would have OPEN or CLOSED contacts.
Primarily, the DTT function operates based on the temperature reading from the Defrost Termination Sensor.
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 consid-
ered closed. This step may not have to be executed. Once the DTT is consid-
ered 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.
P10 Tests - Frozen Mode Tests:
P10-0
Frozen Mode
Heat Test
If the container temperature is below 7.2
C (45
F), the setpoint is changed to
7.2
C., and a 180 Minute timer is started. The control will then be placed in the
equivalent 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 pro-
ceeds to test 10-1.
P10-1 Frozen Mode
Pulldown Test
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 before
the 180 minute timer expires. Otherwise, the test fails. Upon failure and when ini-
tiated by an automatic Pre-trip sequence, P10-1 will auto-repeat once by starting
P10-0 over again.
P10-2
Frozen Mode
Maintain
Temperature Test
Test P10-1 must pass for this test to execute.
Same as for test 8-2 except the control temperature is the return probe temper-
ature.
The average error must be +/-1.6
C. If the DataCORDER supply temperature
probe is invalid, the test fails and the control probe temperature will be recorded
as -50
C (
−
58
F). Upon failure and when initiated by an automatic Pre-trip se-
quence, P10-2 will auto-repeat by starting P10-0 over again.
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Page 108: ...7 2 T 364 Based on Drawing 62 11753 Figure 7 2 SCHEMATIC DIAGRAM ...
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