Mitsubishi Electric MCF-GA35VB Service Manual page 11

9-2. Instruction of troubleshooting
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Outdoor unit
Outdoor unit
operates in
doesn't
only Test Run
operate
operation.
even in
Test Run
operation.
Check room
Check of
temperature
wiring
thermistor.
diagram of
Refer to 9-6.
outdoor
"Test point
unit.w
diagram and
voltage".
w Before checking the outdoor unit, make sure if
any signal or power is being transmitted from
the indoor unit.
9-3. Troubleshooting check table
OPERATION INDICATOR
lamp
Before taking measures, make sure that the symptom reappears, for accurate troubleshooting.
Self check table
Abnormal
No. Operation indicator lamp
point
Indoor coil
2-time flash
thermistor
1
Room
temperature
2.5-second OFF
thermistor
4-time flash
Indoor
control
2
system
2.5-second OFF
When the
remote
controller is
pressed
or when the
EMERGENCY
OPERATION
switch is
pressed,
Indoor unit
the fan doesn't
operates, when
rotate, with
the
OPERATION
EMERGENCY
INDICATOR
OPERATION
lamp on.
switch is
pressed.
Refer to 9-5.B
Refer to 9-5.A
"Check of
"Check of
remote
indoor fan
controller
motor".
and receiver
P.C. board".
As for outdoor unit MUCF type, refer to service manual OB383.
Symptom
Outdoor unit
does not
operate.
Outdoor unit
does not
operate.
11
Indoor unit
doesn't
receive the
signal from
remote
controller.
Indoor unit
doesn't
operate,
when the
EMERGENCY
OPERATION
switch is
pressed.
Refer to 9-5.C
"Check of
indoor
electronic
control
P.C. board".
Detection method
Detect Indoor coil/room temperature
thermistor short or open circuit.
When it cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.
OPERATION
INDICATOR
lamp on the
indoor unit is
flashing
on and off.
2-time flash
4-time flash
Cause:
Cause:
Indoor unit
Indoor unit
• Trouble of
• Trouble of
indoor unit
room
control
temperature/
system
indoor coil
thermistor
Check room
Replace the
tempreture
indoor
thermistor and
electronic
indoor coil
control
thermistor.
P.C. board.
Refer to 9-6.
"Test point
diagram and
voltage".
Checkpoint
• Check the resistance of
thermistor.
• Reconnect the connector.
• Check the indoor electronic
control P.C.
• Check the indoor electronic
control P.C. board.