11
8-2. 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.
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" on
page 17 or 18.
Refer to
"Check of
inverter/
compressor".
Refer to
"Check of
R.V. coil".
Refer to
B
"Check of
remote controller
and receiver
P.C. board"
on page 14.
Flash on and
off at 0.5-
second
intervals
Cause:
Indoor/
Outdoor unit
• Mis-wiring
or trouble of
serial signal
2-time flash
Cause:
Indoor unit
• Trouble of
room
temperature/
indoor coil
thermistor
Check room
temperature
thermistor
and indoor
coil
thermistor.
Refer to
"Test point
diagram and
voltage"
on page 17
or 18.
4-time flash
Cause:
Indoor unit
• Trouble of
indoor unit
control
system
Replace the
indoor
electronic
control P.C.
board.
Refer to
D
"How to
check mis-
wiring and
serial signal
error (When
outdoor unit
doesn't
work)" on
page 15 or
16.
Unit doesn't
operate
normal
operation in
COOL or
HEAT mode.
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
"Check of
outdoor
thermistors".
Check the
inverter P.C.
board or
outdoor
electronic
control P.C.
board.
5-time flash
Cause:
Outdoor unit
• Outdoor
power
system
abnormality
Refer to
"Check of
inverter/
compressor".
As for outdoor units MUZ-A12YV and MUZ-A12YVH, refer to service manual OB328 REVISED EDITION-A.
As for outdoor units MUZ-A18YV and MUZ-A24YV, refer to service manual OB346 REVISED EDITION-A.
1. Check indoor / outdoor
connecting wire.
(Check if the power
is supplied to the
indoor unit.)
2. Refer to
C
"Check of indoor
electronic control
P.C. board"
on page 14.
OB344A--1.qxp 04.6.14 1:04 PM Page 11
