18
9-2. Instruction of troubleshooting
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Indoor unit
doesn't receive
the signal from
remote controller.
Indoor unit
operates.
Outdoor unit
doesn't operate
normally.
OPERATION
INDICATOR
lamp on the
indoor unit is
flashing on
and off.
Outdoor unit
operates in
only Test Run
operation.
W
Indoor unit
operates,
when the
EMERGENCY
OPERATION
switch is
pressed.
Indoor unit
doesn't operate,
when the
EMERGENCY
OPERATION
switch is
pressed.
Check room
temperature
thermistor.
Refer to
"Test point
diagram and
voltage" .
Refer to
"Check of
remote
controller
and receiver
P.C. board".
2-time flash
Cause:
Indoor unit
• Trouble of
room temp-
erature/
indoor coil
thermistor
3-time flash
Cause:
Indoor unit
• Trouble of
indoor fan
motor
Check room
temperature
thermistor
and indoor
coil thermis-
tor.
Refer to
"Test point
diagram and
voltage".
Refer to
"Check of
indoor fan
motor".
1. Check indoor /
outdoor
connecting wire.
2. Refer to
"Check of indoor
electronic control
P.C. board".
Outdoor unit
doesn't
stop even
if indoor unit
stops.
Check of
wiring diagram
of outdoor unit
(Refer to 6.
WIRING
DIAGRAM.)
Flash on and
off at 0.5-second
intervals
Cause:
Wrong setting
of switch (SW2-
2
)
on the electronic
control P.C. board.
Refer to 9-4.
A
"Check of
MU & MUX TYPE /
MUH & MXZ TYPE
SWITCH OVER "
(When
outdoor unit
doesn't operate.).
4-time flash
Cause:
Indoor unit
• Trouble of
indoor unit
control
system
Replace the
indoor
electronic
control
P.C. board.
W
"Test run operation"
means the operation
within 30 minutes
after
EMERGENCY
OPERATION
switch is pressed.
Refer to indoor
unit service
manual.
MU-GA20VB
MU-GA25VB
MU-GA35VB
OB386B.qxp 06.4.25 11:23 AM Page 18
