Carrier NDK33BN0KB, Operation & Service Manual

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62-61753-21 7-45
Alarm
NO.
Steps ALARM / CAUSE CORRECTIVE ACTION
76 CONDENSER MOTOR OVERHEATED

TRIGGER-ON: One or both of the condenser fan motor Internal Protectors (IP-CDM1 or 2) circuit is
open.

UNIT CONTROL: Engine operation: engine and unit shutdown and alarm.
Standby operation: refrigeration system shutdown and alarm with PSCON
still energized.

RESET CONDITION: Auto Reset when motor overload input is within limits, or change to engine op-
eration, 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 (refer to 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 Condenser Fan Blades for Free Operation
a. Visually inspect condenser fan
blades for any foreign material or
damage or anything that will pre-
vent the blade and motor from
turning freely
Fan blade must be in good condition.
No material obstructing movement
No ice build-up preventing blade rotation.
2 Check For Power At 4MP2
a. If 12VDC. Alarm should have cleared itself.
b. If no power (0VDC.) Continue with step 2 below.
3 Check IPC circuit
a. Check MPQC9. There should be 12 VDC from MPQC9 to Ground.
b. Use Component Test Mode to test
actual current draw of the circuit.
(Refer to Section 5.1.2.)
Component FET or board LED (refer to Table 5-1)
must be illuminated.
View current draw in Data List.
Refer to Section 2.12 for normal current values.
c. Unplug the connector to condenser
fan motor 1 (CDM1) and check
voltage on pins 4-5 in the engine
harness connector.
12 VDC between pin 4 and pin 5 indicates the open
circuit is in the IP for CDM1.
d. Test continuity through CDM1 IP at
pins 4-5 in the fan motor harness
connector.
Should be 0 Ohms. If condenser fan motor 1 is ex-
tremely warm, allow it to cool off, then recheck IP con-
tinuity.
e. Test continuity through IPC. Should be 0 Ohms. If either condenser fan motor is
extremely warm, allow it to cool off, then recheck IPC
continuity.
f. Test IP circuit from condenser fan
motor wires to microprocessor.
12 VDC at 4MP2.
4 Check Condenser Fan Motor Contactor
a. Inspect the wire connections to the
contactor.
No signs of overheating of the contactor. Wiring is
routed correctly to the contactor.
b. Check tightness of the contactor
wire connections.
Tighten with screwdriver and check for discoloration of
wires.
5 Perform Pretrip
a. Clear Active Alarm list, then run
Pretrip & check for any new
alarms.
Any active alarms must be corrected and cleared be-
fore proceeding.
Additional steps on the next page.