Mitsubishi Electric MUH-GA35VB Service Manual page 23

10-2. Instruction of troubleshooting
MUH-GA20VB -
E1
MUH-GA25VB -
E1
MUH-GA35VB -
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 10-4.
temperature
A "Check of
thermistor.
outdoor unit".
Refer to 10-5
"Test point
diagram and
voltage".
Flash on and off at 2-time flash
Cause:
0.5-second intervals
Indoor unit
Cause:
• Trouble of
Indoor/Outdoor unit
• Mis-wiring or
trouble of serial
signal
Refer to 10-4. D
"How to check
mis-wiring and
serial signal
error (When
outdoor unit
doesn't work)".
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
doesn't
stop even
if indoor unit
stops.
Refer to 10-4.
B "Check of
outdoor unit".
3-time flash
Cause:
Indoor unit
• 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 10-5
"Test point
diagram and
voltage".
Indoor unit
doesn't receive
the signal from
remote controller.
Unit doesn't
Indoor unit
operate
operates,
normal when the
operation in EMERGENCY
COOL or OPERATION
HEAT mode. switch is
pressed.
Refer to 10-4.
Refer to
C "Check of
"Check of
R.V. coil".
remote
controller
and receiver
P.C. board".
4-time flash
6-time flash
Cause:
Cause:
Indoor unit
Outdoor unit
• Trouble of
• Trouble of
indoor unit
thermistor
control
in outdoor
system
unit
Replace the
Refer to 10-4.
indoor
E"Check of
electronic
outdoor
control
thermistor".
P.C. board.
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.
As for indoor unit
MSC type,
1. Check indoor /
refer to service
outdoor
manual OB385
connecting wire.
or OB393.
2. Refer to
"Check of indoor
electronic control
P.C. board".
7-time flash
Cause:
Outdoor unit
• Trouble of
outdoor
control
system
Replace the
deicer
P.C. board.