Mitsubishi Heavy Industries FDT71VNXVD Service Manual page 78

Error code
Indoor control PCB
Remote controller:
E41
Outdoor control PCB
Outdoor
inverter
1. Applicable model
Single phase model only
2. Error detection method
Anomalous rise of the internal
power transistor temperature
3. Condition of Error displayed
When anomalous rise of the
internal power transistor
temperature is detected 5 times
within 1 hour.
4. Presumable cause
• Defective inverter PCB
• Defective outdoor fan motor
• Improperly fixed power
transistor radiator fin
• Delective power transistor
temperature thermistor
• Inadequate installation space
Note:
LED Green
Keeps flashing
Keeps flashing
Yellow LED
6 times flash or 2 times flash
PCB
5. Troubleshooting
Is it possible to
reset the error for about 10 minute after the
compressor stopped?
YES
Is the
installation space of outdoor
unit enough?
YES
Is the outdoor fan running?
YES
Are the
characteristics of power transistor temperature
thermistor OK?
YES
Is the power
transistor temperature thermistor connector
connection OK?
YES
Is it OK the fixing
to power transistor radiator fin?
・ Fixed screw
・ Application of radiation
silicone
YES
YES
Does it recur?
* Characteristics of power transistor temperature thermistor
(Broken wire)
Temperature-resistance characteristics
200
180
160
140
120
100
80
60
40
20
0
0 20
(Shot circuit)
Red
Content
Stays OFF
Power transistor overheat
1 time flash
(Single phase model only)
Diagnosis
NO
NO Defective inverter PCB
Is it reset?
NO
NO
Correct.
NO
Replace the fan motor or outdoor control
PCB.
NO
Replace the power transistor
temperature thermistor.
NO
Connect.
NO
NO
40 60 80 100 120 140
Temperature (°C)
78 88
– –
'10 • PAC-SM-137A
Countermeasure
OK
YES
Replace power transistor.
Fix properly.
OK