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10-3. Troubleshooting check table
Operation Indicator
· Flashing of the OPERATION INDICATOR lamp (on the left-hand side) indicates possible abnormalities.
· The OPERATION INDICATOR lamp (on the left-hand side) is lighting during normal operation.
flashing
• The following indication does not depend on the shape of lamp.
❈
Before taking measures, make sure that the symptom reappears, for accurate troubleshooting.
Self check table
No.
1
2
4
6
7
Symptom
Operation indicator lamp
Detection method
Checkpoint
0.5-second ON
0.5-second OFF
MUH or
MXZ type
Mis-wiring
MUH or
MXZ type
Defrost
thermistor
MUH or
MXZ type
Outdoor
control
system
error
When serial signal stops for 4 to 5 seconds af-
ter 1st on of 52C relay by POWER turning on.
When the defrost thermistor shorts or opens
after the compressor start-up.
When it cannot properly read data in the non-
volatile memory of outdoor electronic control
P.C. board.
When the operation mode of each indoor unit
is differently set to COOL(includes DRY) and
HEAT at same time, the operation mode of
indoor unit that has operated at first has the
priority.
●
Check outdoor DEICER P.C.
board and others.
●
Check resistance of
thermistor.
●
Reconnect connector.
Refer to service manual
OB331 or OB319.
●
Check outdoor DEICER P.C.
board and others.
Refer to service manual
OB331 or OB319.
●
Unify the operation mode.
●
Check switch SW2-
2
.(MU &
MUX type or MUH & MXZ
type)
●
Check wiring (visual check
and conductivity check).
●
Check indoor electronic
control P.C.board.
●
Check outdoor DEICER P.C.
board and others.
●
Check electrical parts.
●
Check resistance of
thermistor.
●
Reconnect connector.
●
Check indoor electronic
control P.C.board.
3
Indoor coil
thermistor
Room
temperature
thermistor
8
MXZ type
Outdoor
refrigerant
system
error
When the compressor operation has been in-
terrupted by LEV protection continuously 5
minutes, the compressor stops operation.
Abnormal
point
Outdoor unit
does not run.
Outdoor unit
does not run.
Outdoor unit
does not run.
Outdoor unit
does not run.
Outdoor unit
does not run.
Outdoor unit
does not run.
MUH or
MXZ type
Serial
signal
1-time flash
2.5-second OFF
2-time flash
2.5-second OFF
When serial signal from outdoor unit stops for
4 to 5 seconds.
Detect Indoor coil/room temperature thermis-
tor short or open circuit every 8 seconds dur-
ing operation.
3-time flash
2.5-second OFF
Indoor fan motor
repeats 12 sec-
onds ON and 3
minutes OFF.
When the indoor
fan motor
breaks, the fan
keeps stopping.
When rotational frequency feedback pulse
signal is not emit during 12-second indoor fan
operation.
When the compressor operation is
continuously three times interrupted by over
current protection within 1 minute after start-
up , it stops operation.
●
Disconnect connector
CN211 and then check
connector CN121
2
-
3
to
make sure rotational
frequency feedback signal of
1.5V or over exists.
●
Check indoor electronic
control P.C. board.
●
Check indoor fan motor.
●
Reconnect connector.
●
Check the inverter output.
●
Check the compressor.
Indoor fan
motor
6-time flash
2.5-second OFF
●
Refer to "Check of LEV".
●
Check refrigerant circuit and
refrigerant amount.
●
Check outdoor electronic
control P.C. board.
Refer to service manual
OB319.
5
5-time flash
2.5-second OFF
Operation Indicator
MXZ type
Operation
mode
setting
Lighted
Flashing
Outdoor unit
operates but
indoor unit
does not run.
7-time flash
2.5-second OFF
10-time flash
2.5-second OFF
MXZ type
Outdoor
power
system
2.5-second OFF
OB329-1.qxp 03.12.3 1:16 PM Page 21
