Mitsubishi MUZ-A18YV Service Manual page 31

10-2. Instruction of troubleshooting
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Outdoor unit
doesn't
Outdoor unit
operate
operates in
even in
only Test Run
Test Run
operation.
operation.
Check room
Refer to E
temperature
thermistor. "Check of
Refer to inverter/
"Test point compressor"
diagram and on page 38.
voltage".
Flash on and 2-time flash
Cause:
off at
Indoor unit
0.5-second
intervals • Trouble of
room temp-
Cause:
erature/
Indoor/
Outdoor unit indoor coil
thermistor
• Mis-wiring
or trouble of
serial signal
Refer to B
Check room
temperature
"How to
thermistor
check
and indoor
mis-wiring
coil thermis-
and serial
tor.
signal error
Refer to
(When
"Test point
outdoor unit
diagram and
doesn't
voltage".
work)".
As for indoor unit MSZ type, refer to service manual OB345.
As for indoor unit MCFZ type, refer to service manual OB344 REVISED EDITION - A.
Indoor unit operates.
Outdoor unit doesn't
operate normally.
Unit doesn't
Indoor unit
operate
operates, when
normal
the EMERGENCY
operation in
OPERATION
COOL or
switch is pressed.
HEAT mode.
Refer to
Refer to C
"Check of
"Check of
remote controller
R.V. coil"
and receiver
on page 37.
P.C. board".
MSZ type 4-time flash
3-time flash Cause:
Cause: Indoor unit
Indoor unit • Trouble of
• Trouble of indoor unit
indoor fan control
motor system
Refer to Replace the
"Check of indoor
indoor fan electronic
motor". control
P.C. board.
31
Indoor unit
OPERATION INDICATOR
doesn't receive
lamp on the indoor unit is
the signal from
flashing on and off.
remote controller.
Indoor unit
doesn't 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
"Check of indoor
electronic control
P.C. board".
6-time flash
5-time flash
Cause:
Cause:
Outdoor unit
Outdoor unit
• Trouble of
• Outdoor
thermistor
power
in outdoor
system
unit
abnormality
Refer to E Refer to F
"Check of "Check of
inverter/ outdoor
compressor" thermistors"
on page 38. on page 39.
7-time flash
Cause:
Outdoor unit
• Trouble of
outdoor
control
system
Replace the
outdoor
electronic
control P.C.
board.