Carrier NDK33BN0KB, Operation & Service Manual

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62-61753-21 7-44
Alarm
NO.
Steps ALARM / CAUSE CORRECTIVE ACTION
75 COMP MOTOR OVERLOAD

TRIGGER-ON: If alarm A22, A27 and/or A28 was triggered with current below 5.5 amps, this alarm
will also trigger or on restart from alarm A22, A27 and/or A28 trigger on if compressor current does
not rise above 1 amp.

UNIT CONTROL: Engine operation: engine and unit shutdown and alarm. Standby operation: refrig-
eration system shutdown and alarm with PSCON still energized.
NOTE
The compressor motor is fitted with an internal line break that may have caused
this alarm. The line break is an auto reset device. Additional time may be re-
quired to reduce winding temperature to the reset temperature of this device.

RESET CONDITION: Auto reset after 30 minutes alarm may be manually reset via keypad or by turn-
ing 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 For A-22. A27 and/or A28 (Check Download)
a. A22, A27 and/or A28 will always
cause this alarm to activate
Review steps for triggered alarms and correct if neces-
sary.
2. Check Compressor Operation
a. Start unit. Check voltage and current on each phase, must be
greater than 0 and less than 16 amps. (Compressor is
operating.)
3.
Check Compressor Motor Contactor
a. Check condition and wiring Repair/replace as required.
4.
Check Motor Windings
a. Check phase to phase Reading as specified in Section 2.11.