Mitsubishi Electric MSH-A18ND Service Manual page 11

8-2. Instruction of troubleshooting
Start
Indoor unit
operates.
Outdoor unit
doesn't
operate.
Outdoor unit
Outdoor unit
operates when
doesn't
the EMERGENCY
operate
OPERATION
when the
switch is pressed.
EMERGENCY
OPERATION
switch is pressed.
Check room
Refer to
temperature
"Check of
thermistor.
outdoor unit".
Refer to 8-6.
"Test point
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
8-5. D temperature
thermistor
"How to
and indoor
check
coil thermis-
mis-wiring
tor.
(When
Refer to 8-6.
outdoor unit
"Test point
doesn't
diagram and
work)".
voltage".
Refer to outdoor unit service manual.
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
Refer to
"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
8-5. A
indoor
"Check of electronic
indoor fan control
motor". 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 8-5.B
"Check of
remote controller
and receiver
P.C. board".
7-time flash
6-time flash
Cause:
Cause:
Outdoor unit
• Trouble of
• Trouble of
thermistor
in outdoor
unit
Refer to
"Check of
outdoor
thermistor".
11
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 8-5.C
"Check of indoor
electronic control
P.C. board".
Outdoor unit
outdoor
control
system
Replace the
deicer
P.C. board.