Carrier VECTOR 6500 Operation & Service Manual page 56

PRETRIP (Continued)
Test 4 - Temperature Sensor Check
Check the condition of all of the system temperature
sensors.
NOTE
Tests 5, 6 an 7 are only performed when unit is
in Engine Operation. When in Standby Opera-
tion, pretrip will skip to Test 8.
Test 5 - Engine Low Speed
The engine starts up in low speed with condenser fans
on. The microprocessor verifies that engine speed is in
low speed range. If the engine is not operating within the
low speed range, the P174 -"CHECK LOW SPEED
RPM" alarm will be activated.
Test 6 - Engine High Speed
The engine switches to high speed and energizes
HTCON1 and HTCON2. The microprocessor verifies
that engine speed is in high speed range. If the engine is
not operating within the high speed range, the P175 -
"CHECK HIGH SPEED RPM" alarm will be activated.
Test 7 - Engine Low Speed 2
The engine switches back to low speed and heaters turn
off. The microprocessor verifies that engine speed is in
low speed range. If the engine is not operating within the
low speed range, the P174 - "CHECK LOW SPEED
RPM" alarm will be activated.
Test 8 - Electric Heater Amperage Check
Each heater will be energized individually and checked
for proper current draw. An alarm will be activated for
any heater not drawing amperage in the expected
range.
Test 9 - Evaporator Fan Motor Amperage Check
The evaporator motor contactor will be energized and
checked for proper current draw. An alarm will be activ-
ated if the evaporator fan motor is not drawing amper-
age in the expected range.
Test 10 - Condenser Fan Motors Amperage Check
The condenser fan motor contactor will be energized
and checked for proper current draw. An alarm will be
activated if the condenser fan motors are not drawing
amperage in the expected range.
Test 11 - Check Compressor Suction Modulation
Valve (CSMV)
This test ensures that the CSMV is opening and closing
properly. If suction pressure doesn't change as
expected with CSMV closed then the P180 - "CHECK
SUCTION MOD VALVE" alarm will be activated. This
test may take several minutes.
Test 12 - Electronic Expansion Valve (EVXV)
This test checks the operation of the EVXV. If valve
doesn't test properly the P177 - "CHECK EVAP SU-
PERHEAT" alarm will be activated.
Test 13 - Unloaders
This test checks the operation of the unloaders. If suc-
tion and discharge pressures do not change when UL1
and UL2 are energized and de-energized, the P178 -
"CHECK UL1" or P191 - "CHECK UL2" alarm will be ac-
tivated.
Test 15 - Check For Other Alarms
The alarm list is checked for any non-pretrip alarms that
may have occurred during the Pretrip test. If any
operational alarms occurred, Pretrip will display FAIL,
and the technician will need to review the Alarm List and
take necessary and appropriate action to clear them.
Test 15 will last about five seconds.
Pretrip Termination
When the Pretrip cycle is completed, the unit will return
to normal temperature control operation. "PRETRIP
PASS" will be displayed until the operator presses any
key. In the event that the Pretrip test triggered an
alarm(s), either "PRETRIP FAIL & COMPLETE" (if the
entire Pretrip cycle was completed), or "PRETRIP FAIL
IN TEST XX", (if the Pretrip cycle was aborted by an
alarm before it was completed) will be displayed.
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