Carrier VECTOR 6500 Operation & Service Manual page 184

Alarm
Steps
NO.
77 EVAP MOTOR OVERHEATED
•
TRIGGER–ON: The evaporator fan motor Internal Protector (IP-EVM) is open.
•
UNIT CONTROL:
•
RESET CONDITION: Auto Reset after a 15 minute off time when motor overload input is within
limits or alarm may be manually reset via keypad or by turning the unit off, then back on again.
NOTE: Follow the steps below until a problem is found. Once a repair or correction has been made, the active
alarm should clear itself (see reset condition above). Operate the unit through the appropriate modes to see if
any active alarm occurs. Continue with the steps below as necessary.
1 Check Evaporator Fan Blades for Free Operation
Visually inspect evaporator fan for
any foreign material or damage or
anything that will prevent the blade
and motor from turning freely
2 Check For 12 VDC At 4MP3
a. If 12VDC
b. If no power (0VDC)
3 Check IPC Circuit
a. Use Component Test Mode to ener-
gize Evaporator Motor Contactor
circuit. (Refer to Section 5.2.2.)
b. Unplug the connector to the evapo-
rator fan motor and check voltage
on IP-EVM (white) wire.
c. Check MPQC9.
d. Test continuity through IPC.
e. Test IP circuit from evaporator fan
motor junction box to microproces-
sor.
4 Check Evaporator Fan Motor Contactor
a. Inspect the wire connections to
the contactor. (See wiring schem-
atic Section 10.)
b. Check tightness of the contactor
wire connections
5 Perform Pretrip
Clear Active Alarm list, then run Pre-
trip & check for any new alarms.
Additional steps on the next page.
Alarm/Cause
Engine and Standby Operation: shutdown and alarm
7−51
Corrective Action
Blower wheel must be in good condition.
No sticks or other material obstructing its movement
No ice build-up preventing blade rotation.
Alarm should have cleared itself.
Continue with step 2 below.
FET 20 will be on.
12 VDC between pin 4 in the engine harness
connector and Ground.
There should be 12 VDC from MPQC9 to Ground.
Should be 0 Ohms. If the evaporator fan motor is
extremely warm, allow it to cool off, then recheck IPC
continuity.
12 VDC at 4MP3
No signs of overheating of the contactor. Wiring is
routed correctly to the contactor.
Tighten with screwdriver and check for discoloration
of wires.
Any active alarms must be corrected and cleared be-
fore proceeding.
62-11389