Carrier NDK33BN0KB, Operation & Service Manual

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62-61753-21 7-54
Alarm
NO.
Steps ALARM / CAUSE CORRECTIVE ACTION
100 OVERLOAD/GROUND FAULT

TRIGGER-ON: The SROS is in the START / RUN position and the overload and ground fault detector
is reading more than 40 Amps on any A/C current leg OR there is A/C voltage leaking to ground of
more than 150 mAmps.

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 in engine mode. Alarm may be manually reset via Keypad or, alarm
may be reset 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 Overload Ground Fault Detector (OGF) LED
a. Check the LED. LED is Off - Circuit Overload is detected. Start with
Step 2
below.
LED is On - Ground Fault is detected. Start with Step 3
below.
2 Check For Electrical Overload
a. Check high voltage amp draw from
GENCON if running on engine or
PSCON2 if running on standby.
Must be less than 40 Amps.
3 Check For High Voltage Short To Ground
a. Check resistance from from T1, T2
and T3 of ALL High voltage
contactors to ground.
Reading must be greater than 25.000 Ohms.
b. Perform Megohmmeter test on all
high voltage circuits.
Disconnect from standby power source if required.
Follow Magohmmeter manufacturers instructions.
4 Perform Pretrip Check
a. Clear Active Alarm list, then run
Pretrip & check for any new
alarms.
Note during which test Alarm 100 occurs.
b. Further test circuit from Steps
above.
Use a megohmmeter to test.
5 Check Overload / Ground Fault Device
a. With the engine OFF and standby
power disconnected, place the
SROS in the START / RUN
position.
Must have 12 VDC at HC19 and 2MP26.