Mitsubishi Electric MUH-A07YV-E1 Service Manual page 23

11-2. Instruction of troubleshooting
MUH-A07YV -
E1
MUH-A09YV -
E1
MUH-A12YV -
E1
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Outdoor unit Outdoor unit
operates in doesn't
only Test Run operate
operation. even in
Test Run
operation.
Check room Refer to A
temperature
"Check of
thermistor.
outdoor unit"
Refer to
on page 24.
"Test point
diagram and
voltage".
1-time flash
Flash on and
off at 0.5- Cause:
second
Outdoor /
intervals
Indoor unit
Cause:
• Trouble of
Indoor/
serial signal
Outdoor unit
• Mis-wiring
Refer to D "How to check
mis-wiring and serial signal
error (When outdoor unit
doesn't work)" on page 26.
W1
W1.<The case of the trouble of the serial signal>
When the power is turned off and then turned on again, the indication shows "the trouble of mis-wiring".
Indoor unit
operates.
Outdoor unit
doesn't operate
normally.
Outdoor unit Unit doesn't
doesn't operate
stop even normal
if indoor unit operation in
stops. COOL or
HEAT mode.
Refer to C
Refer to B
"Check of
"Check of
R.V. coil"
outdoor unit"
on page 25.
on page 25.
2-time flash
3-time flash
Cause:
Cause:
Indoor unit
Indoor unit
• Trouble of
• Trouble of
room temp-
indoor fan
erature/
motor
indoor coil
thermistor
Check room
Refer to
temperature
"Check of
thermistor
indoor fan
and indoor
motor".
coil thermis-
tor.
Refer to
"Test point
diagram and
voltage".
Indoor unit
doesn't receive
the signal from
remote controller.
Indoor unit
operates,
when the
EMERGENCY
OPERATION
switch is
pressed.
Refer to
"Check of
remote
controller
and receiver
P.C. board".
7-time flash
6-time flash
Cause:
Cause:
Outdoor unit
Outdoor unit
• Trouble of
• Trouble of
outdoor
thermistor
control
in outdoor
system
unit
Refer to E
Replace the
"Check of deicer
outdoor P.C. board.
thermistor"
on page 27.
23
OPERATION
INDICATOR
lamp on the
indoor unit is
flashing on
and off.
Indoor unit
doesn't operate,
when the
EMERGENCY
OPERATION
switch is
pressed.
1. Check indoor /
outdoor
connecting wire.
2. Refer to
"Check of indoor
electronic control
P.C. board".
As for indoor unit,
refer to service
manual OB329.