Mitsubishi Electric MUFZ-KJ-NAHZ Series Service Manual page 25

9-3. INSTRUCTION OF TROUBLESHOOTING
Start
Indoor unit
operates.
Outdoor unit
does not
operate.
Outdoor unit
Outdoor unit
operates only
does not
in Test Run
operate
operation.
even in
Test Run
operation.
Refer to
Check room
"How to check
temperature
inverter/
thermistor.
compressor".
Refer to 9-7.
"Test point
diagram and
voltage".
Left lamp
Left lamp
Flash ON and
2-time flash
OFF at
Cause:
0.5-second
Indoor unit
intervals
Cause:
room temp-
Indoor/
erature/
Outdoor unit
indoor coil
thermistor
or trouble
of serial signal
Check room
Refer to 9-6.
temperature
"How to
thermistor
check
and indoor
miswiring
coil thermis-
and serial
tor.
signal error
Refer to 9-7.
(when
"Test point
outdoor unit
diagram and
does not
voltage".
work)".
Indoor unit does
Indoor unit operates.
not receive
Outdoor unit does
the signal from
not operate normally.
remote controller.
Indoor unit
Unit does
operates, when
not operate
EMERGENCY
normal
OPERATION
operation in
switch is pressed.
COOL or
HEAT mode.
Refer to
Refer to 9-6.
"Check of
"Check of
R.V. coil".
remote controller,
display receiver
P.C. board and
indoor control
P.C. board".
Left lamp
Left lamp
3-time flash 4-time flash
Cause:
Cause:
Indoor unit Indoor unit
indoor fan indoor unit
motor
control
system
Refer to 9-6. Replace the
"Check of indoor
indoor fan electronic
motor". control
P.C. board.
OPERATION INDICATOR
lamp on the indoor unit is
flashing ON and OFF.
Indoor unit
does not operate,
when
EMERGENCY
OPERATION
switch is pressed.
1. Check indoor / outdoor
connecting wire.
(Check if the power
is supplied to the
indoor unit.)
2. Refer to 9-6.
"Check of indoor
electronic control
P.C. board and indoor
fan motor".
Left lamp Left lamp
5-time flash 6-time flash
Cause: Cause:
Outdoor unit Outdoor unit
power thermistor
system in outdoor
abnormality unit
Refer to
Refer to
"How to check
"Check of
the inverter/
outdoor
compressor".
thermistors".
25
If blinking of OPERATION
INDICATOR lamp cannot be
checked, it can be checked with
failure mode recall function.
"Test Run operation" means the
operation within 30 minutes after
EMERGENCY OPERATION switch
is pressed.
Refer to outdoor unit service manual.
Left lamp Left lamp
7-time flash 14-time flash
Cause: or more
Outdoor unit Cause:
Outdoor unit
outdoor
control abnormality
system
Check
Replace the
"Flow chart of
inverter P.C.
the detailed
board or
outdoor unit
the outdoor
failure mode
electronic
recall function."
control P.C.
board.