Service manual

12
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Indoor unit
doesn't receive
the signal from
remote controller.
OPERATION INDICATOR
lamp on the indoor unit is
flashing on and off.
Outdoor unit
operates in
only Test Run
operation. w
MU-A30ND
Outdoor unit
doesn't
operate
even in
Test Run
operation.w
Indoor unit
operates, when
EMERGENCY
OPERATION
switch is pressed.
Indoor unit
doesn't operate,
when
EMERGENCY
OPERATION
switch is pressed.
Check room
temperature
thermistor.
Refer to 8-6.
"Test point
diagram and
voltage".
Refer to
"Check of
outdoor unit".
Refer to 8-5. B
"Check of
remote controller
and receiver
P.C. board".
MS-A30ND
Flash on and
off at 0.5-second
intervals
Cause:
Indoor/
Outdoor unit
• Mis-wiring
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
MU-A30ND
6-time flash
Cause:
Outdoor unit
• Trouble of
thermistor
in outdoor
unit
MU-A30ND
7-time flash
Cause:
Outdoor unit
• Trouble of
outdoor
control
system
Refer to
8-5. D
"How to
check
mis-wiring
(When
outdoor unit
doesn't work)".
Check room
temperature
thermistor
and indoor
coil thermis-
tor.
Refer to 8-6.
"Test point
diagram and
voltage".
Refer to
8-5. A
"Check of
indoor fan
motor".
Refer to
"Check of
outdoor
thermistor".
Replace the
deicer
P.C. board.
MU-A30ND
10-time flash
Cause:
Outdoor unit
• Trouble of
low discharge
temperature
protection
Refer to
"Check of
LEV".
4-time flash
Cause:
Indoor unit
• Trouble of
indoor
control
system
Replace the
indoor
electronic
control
P.C. board.
1. Check indoor /
outdoor
connecting wire.
2. Check of outdoor
fuse.
(MU-A18/A24ND)
3. Refer to 8-5. C
"Check of indoor
electronic control
P.C. board".
Refer to
"Check of
outdoor unit".
Refer to
"Check of
solenoid
valve coil".
Refer to outdoor unit service manual.
"Test Run operation" means the operation within 30 minutes after EMERGENCY OPERATION switch is pressed.w
MU-A24ND - S2
MU-A30ND
Outdoor unit
doesn't
stop even
if indoor unit
stop.
Indoor unit
operates.
Outdoor unit
doesn't operate
normally.
MU-A30ND
Outdoor unit
repeats start
and stop.
8-2. Instruction of troubleshooting
OB404A--1.qxp 06.4.26 6:01 PM Page 12