Troubleshooting Check Table - Mitsubishi Electric MSZ-FD25VA Service Manual

10-4. TROUBLESHOOTING CHECK TABLE

Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
When the indoor unit has started operation and the following detection method has detected an abnormality (the first detection
after the power ON), the indoor electronic control P.C. board turns OFF the indoor fan motor with OPERATION INDICATOR
lamp flashing.
L AREA R
Abnormal
No. Operation indicator lamp
point
POWER lamp flashes.
0.5-second ON
Miswiring
1 or serial
signal
0.5-second OFF
Indoor coil
POWER lamp flashes.
thermistor
2-time flash
2
Room
temperature
thermistor
2.5-second OFF
POWER lamp flashes.
3-time flash
Indoor fan
3
motor
2.5-second OFF
POWER lamp flashes.
Indoor
4-time flash
control
4
system
2.5-second OFF
POWER lamp flashes.
5-time flash
Outdoor
5
power
system
POWER lamp flashes.
6-time flash
Outdoor
6
thermistors
POWER lamp flashes.
Outdoor
7-time flash
control
7
system
POWER lamp flashes.
14-time flash
Other
8
abnormality
2.5-second OFF
Outdoor
POWER lamp lights up.
control
9
system
POWER CLEAN PLASMA
Symptom
Indoor unit
and outdoor
unit do not
operate.
2.5-second OFF
2.5-second OFF
2.5-second OFF
Outdoor unit
does not
operate.
Lighted
Blinking
Not lighted
Condition
The serial signal from the outdoor unit is not
received for 6 minutes.
The indoor coil or the room temperature
thermistor is short or open circuit.
The rotational frequency feedback signal is
not emitted during the indoor fan operation.
It cannot properly read data in the nonvolatile
memory of the indoor electronic control P.C.
board.
It consecutively occurs 3 times that the
compressor stops for overcurrent protection or
start-up failure protection within 1 minute after
start-up.
The outdoor thermistors short or open circuit
during the compressor operation.
It cannot properly read data in the nonvolatile
memory of the inverter P.C. board or the
outdoor electronic control P.C. board.
An abnormality other than above mentioned is
detected.
It cannot properly read data in the nonvolatile
memory of the inverter P.C. board or the
outdoor electronic control P.C. board.
25
Correspondence
• Refer to 10-6.D "How to check
miswiring and serial signal
error".
• Refer to 10-7.the
characteristics of indoor coil
thermistor, and the room
temperature thermistor.
• Refer to 10-6.A "Check of
indoor fan motor".
• Replace the indoor electronic
control P.C. board.
• Refer to "How to check of
inverter/compressor".
Refer to outdoor unit service
manual.
• Check the stop valve.
• Refer to "Check of outdoor
thermistor".
Refer to outdoor unit service
manual.
• Replace the inverter P.C.
board or the outdoor
electronic control P.C. board.
Refer to outdoor unit service
manual.
• Check the stop valve.
• Confirm the abnormality in
detail using the failure mode
recall function for outdoor
unit.
• Check the blinking pattern of
the LED on the inverter P.C.
board or the outdoor
electronic
control P.C. board.