Mitsubishi Electric NTXMMX A AA Series Service Manual page 26

9-3. INSTRUCTION OF TROUBLESHOOTING
Start
Indoor unit
Indoor unit operates.
operates.
Outdoor unit does not
Outdoor unit
operate normally.
does not
operate.
Outdoor unit
Outdoor unit
operates only
does not
in Test Run
operate
operation.
even in
*1
Test Run
operation.
*1
Refer to
Check room
"How to check
temperature
inverter/
thermistor.
compressor".
Refer to 9-7.
"TEST POINT
DIAGRAM AND
VOLTAGE".
Left lamp Left lamp
Left lamp
2-time blink
Blink on and off
3-time blink
at 0.5-second Cause:
Cause:
Indoor unit
intervals
Indoor unit
Cause: • Trouble of
• Trouble of
room temp-
Indoor/
Outdoor unit erature/
indoor coil
• Mis-wiring
or trouble thermistor
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 work)".
voltage".
OBHT802B
Indoor unit
does not receive
the signal from
remote controller.
Indoor unit
Unit does not
operates, when
operate
the emergency
normal
operation switch
operation in
is pressed.
COOL or
HEAT mode.
Refer to 9-6.
Refer to
"Check of
"Check of
remote controller,
R.V. coil".
receiver P.C.
board and
indoor electronic
control P.C.
board".
Left lamp
Left lamp
4-time blink
5-time blink
Cause: Cause:
Indoor unit
• Trouble of
• Outdoor
indoor fan indoor unit
motor control
system
Refer to 9-6. Replace the Refer to
"How to check
"Check of indoor
indoor fan electronic the inverter/
compressor".
motor". control
P.C. board.
OPERATION INDICATOR
lamp on the indoor unit is
blinking on and off.
Indoor unit
does not operate,
when
the 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
7-time blink
6-time blink
Cause:
Cause:
Outdoor unit
Outdoor unit Outdoor unit
• Trouble of
• Trouble of
outdoor
power thermistor
control
system in outdoor
system
abnormality unit
Refer to Replace the
"Check of inverter P.C.
outdoor board or
thermistors". the outdoor
electronic
control P.C.
board.
26
If blinking of OPERATION
INDICATOR lamp cannot be
checked, it can be checked with
failure mode recall function.
*1
"Test Run operation" means the
operation within 30 minutes after
the emergency operation switch
is pressed.
Refer to outdoor unit service manual.
Left lamp
9-time blink
Cause:
Indoor unit
• Trouble of
float sensor
or drain
pump
Refer to 9-6. Check the
"Check of drain pump.
float sensor".
Left lamp
14-time blink
or more
Cause:
Outdoor unit
• Other
abnormality
• Check the
stop valve.
Check
"Flow chart of
the detailed
outdoor unit
failure mode
recall function."