Mitsubishi Electric FDT125VNVF Technical Manual page 448

Indoor display
Error code
E51
Remote controller:
inverter PCB
1. Applicable model
All models
2. Error detection method
When power transistor anomaly
is detected for 15 minutes
continuously
3. Condition of Error displayed
Same as above
4. Presumable cause
• Defective outdoor fan motor
• Defective inverter PCB
• Defective outdoor control
PCB
Note:
RUN light
ON
Green LED
Outdoor
control PCB
Keeps flashing
Yellow LED
Outdoor
6 times flash
5. Troubleshooting
• Model FDC100-140VN
detected between ② and ③
detected after disconnecting
• Model FDC100-140VS
Replace immediately the inverter PCB and the power transistor.
Note(2) How to check the voltage between ② and ③ of CNI3?
TIMER light
Content
4 times flash
Red LED
Inverter and fan motor anomaly
1 time flash
Diagnosis
⑴ ⑵
Is DC15V
on CNI3?
Note(1) Under anomalous conditions,
the voltage becomes less than
NO
DC14V.
⑴
Is DC15V
outdoor fan motor?
447
- -
'12 • PAC-T-174
Countermeasure
Replace inverter PCB
YES
If not solved, replace
Noise filter PCB as well.
Replace outdoor fan motor.
YES
Replace outdoor control PCB
NO
If not solved, replace
inverter PCB as well.
② ： 15V (＋)
③ ： GND (−)
③
②