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3 − 37 T-364
Table 3 − 7 Controller Pre-trip Test Codes (Sheet 4 of 6)
NOTE
P6-6 through P6-10 are conducted by changing status of each valve and comparing suction pressure change
and/or compressor current change with predetermined values. Tests will cause compressor and condenser
fans to cycle on and off as needed to generate the pressure required for individual Pre-trip sub tests. The com-
pressor will start in order to build discharge pressure, followed by compressor pump down sequence. At the
conclusion of compressor pump down sequence, the compressor will shut down and the valve test will start.
P6-6
Economizer
Valve Test
Passes if suction pressure increases a minimum of 4 psia when the valve opens
for 15 seconds.
P6-7
Digital Unloader
Valve Test
Passes if pressure and current changes are within 3 seconds of DUV switch sig-
nal and either the pressure change or the current draw change is above 5 psi or
above 1.5A, respectively.
P6-10
Electronic
Expansion Valve
Test
The test records the suction pressure during the open valve position and passes
if the suction pressure increase is above 3 psi when the valve opens for 10
seconds.
NOTE
P7-0 & P8 are included with “Auto 2 & Auto 3” only. P9-0 through P10 are included with “Auto2” only.
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
High Pressure
Switch (HPS)
Opening Test
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 min-
ute) timer is started. The right display shows Discharge Pressure if the sensor is
configured and valid, else Discharge Temperature. The unit needs to disable Dis-
charge 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.
P7-1
High Pressure
Switch (HPS)
Closing Test
If return temperature greater than -2.4 C (27.7 F), set setpoint to -5.0 C (23 F),
else set setpoint to -30 C ( − 22 F). Restart unit according to normal startup lo-
gic. 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.