Mitsubishi Electric MS-C18TV-E1 WH Service Manual page 30

11-2. 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
temperature
Refer to D
thermistor.
"Check of
Refer to
outdoor unit"
"Test point
on page 33
diagram and
or 34.
voltage" on
page 36.
1. troubleshooting check table
flashing
· Flashing of the OPERATION INDICATOR lamp (on the left-hand side)
Operation Indicator
· The OPERATION INDICATOR lamp (on the left-hand side) is lighting during
Before taking measures, make sure that the symptom reappears for accurate troubleshooting.
Self check table
Abnormal
NO.
point
Indoor coil
2-time flash
thermistor
1
Room
tempera-
2.5-second OFF
ture ther-
mistor
3-time flash
Indoor fan
2
motor
2.5-second OFF
MS-C24TV only
Indoor unit
operates.
Outdoor unit
doesn't operate
normally.
Outdoor unit
doesn't
stop even if
indoor unit
stop.
Refer to E
"Check of
outdoor unit"
on page 35.
indicates possible abnormalities.
normal operation.
Indication
Indoor unit
doesn't receive
the signal from
remote controller.
Indoor unit
Indoor unit
operates,
doesn't operate,
when the
EMERGENCY when the
OPERATION EMERGENCY
switch is OPERATION
pressed. switch is pressed.
1. Check indoor /
Refer to B
outdoor
"Check of
connecting wire.
remote
2. Refer to C
controller
"Check of indoor
and receiver
electronic control
P.C. board"
P.C. board"
on page 32.
on page 33.
Symptom
Detect method
Detect Indoor coil/room tem-
Outdoor unit perature thermistor short or
does not run. open circuit every 8 seconds
during operation.
Indoor fan motor
repeats 12 sec-
onds ON and 3 When rotational frequency
minutes OFF.
feedback signal is not emit
When the indoor during 12-second indoor fan
fan motor operation
breaks, the fan
keeps stopping.
30
OPERATION INDICATOR
lamp on the indoor unit is
flashing on and off.
2-time flash
3-time flash
Cause:
Indoor unit Cause:
• Trouble of
Indoor unit
room temp-
• Trouble of
erature/
indoor fan
indoor coil
motor
thermistor
Check room
temperature
Refer to A
thermistor and
"Check of
indoor coil
indoor fan
thermistor.
Refer to "Test motor"
point diagram
on page 32.
and voltage" on
page 36.
Check point
Check thermistor calibration.
Reconnect connector.
Check indoor electronic control P.C.
board.
Disconnect connector CN211 and then
check connector CN121 2 - 3 to make
sure rotational frequency feedback signal
of 1.5V or over exists.
Check indoor electronic control P.C.
board.
Check indoor fan motor.
Reconnect connector.