Operating instructions

TM 11574A-OI
2-36
Table 2-8 Controller Pre-Trip Test Codes - Continued
Code
No.
TITLE DESCRIPTION
P5-1 Supply Probe Test
Requirements: For units equipped with secondary supply probe only. Pass/Fail
Criteria: The temperature difference between primary and secondary probe
(supply) is compared.
NOTE
If this test fails, “P5-1” and FAIL will be displayed. If both Probe tests
(this and the SUPPLY/ RETURN TEST) pass, because of the multiple
tests, the display will read ’P 5’ ’PASS’.
P5-2 Return Probe Test
Requirements: For units equipped with secondary return probe only.
Pass/Fail Criteria: The temperature difference between primary and secondary
probe (return) is compared.
NOTE
1. If this test fails, “P5-2” and “FAIL” will be displayed. If both Probe tests
(this test and the SUPPLY/ RETURN) pass, because of the multiple
tests, the display will read “P 5,” “PASS.”
2. The results of Pre-Trip tests 5-0, 5-1 and 5-2 will be used to activate or
clear control probe alarms.
P-6 Not Applicable
P6-0 Compressor On
Setup: A current draw test is performed before the compressor is started. The
compressor is started. SMV is opened and another current draw test is
performed.
Pass/Fail Criteria: Passes if the change in compressor current draw is within
the specified range.
P6-H & P6L Not Applicable
P6-2
Suction Modulation
Valve (Open and
Closed)
Setup: The compressor and fans continue to run from the previous test. The
quench valve (if configured) will operate as in normal control mode. The SMV is
closed to 0% open, current and condenser pressure readings are taken. The
SMV is opened to 50% with continuous current and condenser pressure read-
ings taken to establish maximum values. The SMV is returned to 0% open and
final readings are taken.
Pass/Fail Criteria: Passes if the calculated difference in current at the 50%
open position are above a specified value before and after opening of the SMV,
OR the calculated difference in condenser pressure at the 50% open position
are above a specified value before and after opening of the SMV
P6-3 Quench Valve Test
Setup: The compressor suction temperature is measured with the Quench valve
closed. The Quench valve is energized and the suction temperature drop is
checked.
Pass/Fail Criteria: Passes if suction temperature is within the valid range.
P6-4 Not Applicable Not Used
P6-5 Not Applicable Not Used
NOTE P7-0 & P8 are included with the “Auto2 & Auto 3” only. P9-0 through P10 are included with “Auto2” only
P7-0
High Pressure
Switch Closed
Setup: When the unit is running, the condenser fan is de-energized, and a 15
minute timer is started. The right display shows discharge pressure if the unit is
equipped with a discharge pressure transducer (DPT). If no DPT is installed,
the condenser pressure transducer (CPT) reading will be displayed.
Pass/Fail Criteria: The test fails if high pressure switch fails to open in 15
minutes.