Carrier 69NT40-541-505, Operation And Service Manual, Page: 72 / 143

T-368 4–42
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.
NOTE
If unit configured for single evaporator fan operation and either AL11 or AL12 is active at the start of
either test, the test will fail immediately. If AL11 or AL12 become active during the test, the test will
fail upon conclusion of the test.
P4-0
High Speed
Evaporator Fan
Motors On
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 mea-
sured 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.
P4-1
High Speed
Evaporator Fan
Motors Off 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.
P5 Tests - Air Stream Temperature Sensor Tests: Tests the validity of the Air Stream Temperature Sensors.
P5-0
Supply / Return Probe
Test
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 re-
turn and supply probes.
Test passes if temperature comparison falls within the specified range.
NOTE
If this test fails, P50 and FAIL will be displayed. If both Probe tests (this test and
the PRIMARY / SECONDARY) pass, the display will read P5 PASS.
P5-1 Supply Probe Test
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.
NOTE
If this test fails, P51 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
For units equipped with secondary return probe only.
The temperature difference between primary return probe and secondary return
probe is compared.
Test passes if temperature comparison falls within the specified range.
NOTES
1. If this test fails, P52 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 PreTrip tests 50, 51 and 52 will be used to activate or clear
control probe alarms.
P5-3
Evaporator Fan
Direction Test
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.
After 60 seconds this test is forced to PASS irrespective of differential change in
primary supply temperature and primary return temperature.
Test P5-0 must pass before this test is run.
P5-4 - P5-9 Not Applicable
Table 4–7 Controller Pre-Trip Test Codes
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