Power Transistor Overheat; E48 Outdoor Fan Motor Anomaly - Mitsubishi Heavy Industries FDT71VNXWVH Service Manual

Error code
Indoor control PCB
Remote control:
E41
Outdoor control PCB
Outdoor inverter
1. Applicable model
2. Error detection method
When less than DC14V of
the output voltage is detected
between ② and ③ on CNI3,
E41 is displayed.
(See "Note" mentioned below.)
3. Condition of error displayed
Seme as above.
4. Presumable cause
• Inverter PCB anomaly
• Outdoor fan motor anomaly
• Outdoor unit control PCB
anomaly
• Noise filter PCB anomaly
Note:
The "Single phase models" of inverter PAC have no function to output the signal for the power transistor overheat. However
since the power source for the power transistor and the outdoor fan motor is in the same line, when the anomaly of the
outdoor fan motor occurs, E41 is displayed.
LED Green
Keeps flashing
Keeps flashing
Yellow LED
PCB
6-time flash
5. Troubleshooting
Is DC15V detected
between ② and ③ on
CNI3?
NO
Is DC15V
detected after disconnecting
outdoor fan motor?
Note(2) How to check the voltage between ② and ③ of CNI3?
⇒See E51
Red
Content
Stays OFF
1-time flash

Power transistor overheat

Diagnosis
⑴ ⑵
YES
Note(1) Under anomalous conditions,
the voltage becomes less than DC14V.
⑴
YES
NO
106
- -
'19 • PAC-SM-332
Countermeasure
Replace inverter PCB .
If not solved, replace
noise filter PCB as well.
Replace outdoor fan motor.
Replace outdoor unit
control PCB .
If not solved, replace
inverter PCB as well.