Mitsubishi Electric MUH-GA50VB-E1 Service Manual page 26

10-2. Instruction of troubleshooting
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Outdoor unit
doesn't
Outdoor unit
operate
operates only
even in
in Test Run
operation. w
Test Run
operation. w
Check room
Refer to
temperature
thermistor. 10-4.A
Refer to
"Check of
"Test point
outdoor unit".
diagram and
voltage".
Flash on and
2-time flash
off at 0.5-
Cause:
second
Indoor unit
intervals
• Trouble of
Cause:
room temp-
Indoor/
erature/
outdoor unit
indoor coil
• Mis-wiring thermistor
Check room
Refer to
temperature
10-4.D
thermistor
"How to
and indoor
check
coil thermis-
mis-wiring
tor.
(When
Refer to
outdoor unit
"Test point
doesn't
diagram and
work)".
voltage".
Refer to indoor unit service manual.
w"Test Run operation" means the operation within 30 minutes after EMERGENCY OPERATION switch is pressed.
Indoor unit
operates.
Outdoor unit
doesn't operate
normally.
Unit doesn't
Outdoor unit
operate
doesn't
normal
stop even
operation in
if indoor unit
COOL or
stops.
HEAT mode.
Refer to
Refer to
10-4.B
10-4.C
"Check of
"Check of
outdoor unit".
R.V. coil".
3-time flash 4-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.
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
10-4.F
Replace the
"Check of
deicer
outdoor
P.C. board.
thermistor".
26
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".
10-time flash
Cause:
Outdoor unit
MUH-GA80VB
• Trouble of
low discharge
temperature
protection
MUH-GA80VB
Refer to
10-4.E
"Check of
LEV".