30
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.
Outdoor unit
doesn't
operate
even in
Test Run
operation.
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
A
"Check of
outdoor unit"
on page 32 or
33.
Refer to
"Check of
remote controller
and receiver
P.C. board".
Flash on and
off at 0.5-
second
intervals
Cause:
Indoor/
Outdoor unit
• Mis-wiring
Refer to
D
"How to
check
mis-wiring
(When
outdoor unit
doesn't
work)" on
page 35.
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".
4-time flash
Cause:
Indoor unit
• Trouble of
indoor unit
control
system
Replace the
indoor
electronic
control
P.C. board.
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.
Unit doesn't
operate
normal
operation in
COOL or
HEAT mode.
Refer to
B
"Check of
outdoor unit"
on page 34.
Refer to
C
"Check of
R.V. coil"
on page 34
or 35.
As for indoor unit, refer to service manual OB321.
6-time flash
Cause:
Outdoor unit
• Trouble of
thermistor
in outdoor
unit
7-time flash
Cause:
Outdoor unit
• Trouble of
outdoor
control
system
Refer to
F
"Check of
outdoor
thermistor"
on page 36.
Replace the
deicer
P.C. board.
10-time flash
Cause:
Outdoor unit
MUH-A30WV
• Trouble of
low discharge
temperature
protection
MUH-A30WV
Refer to
E
"Check of
LEV" on
page 36.
OB322-1.qxp 03.11.13 4:06 PM Page 30
Summary of Contents for MUH-A18WV
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