Carrier Transicold 69NT40-561-001 Operation And Service Manual page 86

P7 Tests - High Pressure Tests: Unit is run at full capacity without condenser fan running to make sure
that the HPS opens and closes properly.
P7-0 & P8 are included with "Auto 2 & Auto 3" only. P9-0 through P10 are included with "Auto2" only.
P7-0 High Pressure Switch
(HPS) Opening Test
P7-1 High Pressure Switch
(HPS) Closing Test
P8 Tests - Perishable Mode Tests: Pretrip tests P7-0 and P7-1 must have passed or have been
skipped for these tests to execute.
P8-0 Perishable Mode Test
T-340
Table 4–7 Controller Pre-trip Test Codes
NOTE
Test is skipped if sensed ambient temperature is less than 7.2°C (45°F),
return air temperature is less than -17.8°C (0°F), or the water pressure
switch is open.
With the unit running, the condenser fan is turned off and a 900 second (15
minute) timer is started. The right display shows Discharge Pressure if the
sensor is configured and valid, else Discharge Temperature. The unit
needs to disable Discharge Pressure limit and enable Current Limit
checks.
The test fails immediately if:
-Ambient Temperature Sensor invalid
-Composite Return Temperature Sensor invalid
-HPS is open
The test fails if:
-HPS fails to open before 900 seconds total test time.
-Evaporator or Compressor IP Alarm.
-Calculated Dome Temperature exceeds 137.78°C (280°F).
-Discharge pressure exceeds 370 psig.
-Compressor Current exceeds limits
The test passes if HPS opens within the 15 minute time limit.
If return temperature greater than -2.4°C, set setpoint to -5.0°C, else set
setpoint to -30°C. Restart unit according to normal startup logic. Run unit
normally for 120 seconds.
The test passes if the high pressure switch closes within 75 seconds after
end of Test 7-0, else the test fails.
Test P7-0 must pass for this test to execute.
If the control temperature is below 15.6°C, the setpoint is changed to
15.6°C, and a 180 Minute timer is started. The control will then be placed
in the equivalent of normal heating. If the control temperature is above
15.6°C. at the start of the test, then the test proceeds immediately to test
8-1. While in test 8-0 the right display will show the value of the control tem-
perature.
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 8-1.
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