Carrier 69NT40-561-201 Operation & Service Manual page 64

P4 Tests - High Speed Evaporator Fans Current Draw: High speed evaporator fans are turned on, then off.
Current draw must fall within specified range and measured current changes must exceed specified ratios. No
other system components will change state during this test.
High Speed
P4-0 Evaporator Fan
Motors On
High Speed
P4-1 Evaporator Fan
Motors Off
P5 Tests - Air Stream Temperature Sensor Tests: Tests the validity of the Air Stream Temperature Sensors.
Supply/Return
P5-0
Probe Test
P5-1 Supply Probe Test
P5-2 Return Probe Test
Evaporator Fan
P5-3
Direction Test
Table 3−7 Controller Pre-trip Test Codes (Sheet 2 of 6)
Evaporator fans start in the off condition, current draw is measured, then high
speed evaporator fans will be turned on. After 60 seconds the current draw is
measured again. The change in current draw is then recorded.
Test passes if change in current draw in the specified range AND measured cur-
rent changes exceed specified ratios.
If the three phase motors are configured IN, the change ratio test is skipped.
High speed evaporator fans are then turned off. After 10 seconds the current
draw is measured. The change in current draw is then recorded.
Test passes if change in current draw test is in the specified range.
The High Speed Evaporator Fan is turned on and run for eight minutes, with all
other outputs de-energized. A temperature comparison is made between the
return and supply probes.
Test passes if temperature comparison falls within the specified range.
If this test fails, "P5-0" and "FAIL" will be displayed. If both Probe tests (this
test and the PRIMARY/ SECONDARY) pass, display will read "P5" "PASS."
This test if for units equipped with secondary supply probe only.
The temperature difference between primary supply probe and secondary supply
probe is compared.
Test passes if temperature comparison falls within the specified range.
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 "P5" "PASS."
For units equipped with secondary return probe only.
The temperature difference between return temperature sensor (RTS) and return
temperature sensor (RRS) probe is compared.
Test passes if temperature comparison falls within the specified range.
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.
With evaporator fan running on high speed, measure the temperature difference
between the primary supply and primary return probes. Turn the heaters on for
60 seconds then measure the temperature difference between the primary sup-
ply and primary return probes for up to 120 additional seconds.
This is a Pass/Fail test. The test passes if differential of STS is 0.25_C higher
than RTS.
Test P5-0 must pass before this test is run.
NOTE
NOTE
NOTES
3−35
T-364