Mitsubishi Electric MS-07NV -E1 (WH) Service Manual page 38

10-2 Instruction of troubleshooting
Indoor unit oper-
ates. Outdoor unit
doesn't operate.
Outdoor unit Outdoor unit
operates in doesn't oper-
only Test ate even in
Run opera- Test Run
tion. operation.
Refer to
Check room
"Check of
temperature
outdoor unit"
thermistor.
on page 41.
10-2-1 troubleshooting check table
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
38
Indoor unit
doesn't receive
the signal from
remote
controller.
Refer to
B
"Check of
receiver P.C.
board" on page
40.
D
Indication
Outdoor unit
does not run.
Indoor fan
repeats 12 sec-
onds ON and 3
minutes OFF.
When the indoor
fan breaks, the
fan keeps stop-
ping.
Start
OPERATION INDICATOR
lamp on the indoor unit is
flashing on and off.
2-time flash
2.5-second OFF
3-time flash
2.5-second OFF
Cause:Indoor unit
2-time-Room temperature/Indoor coil thermistor trouble
3-time-Indoor fan motor trouble
Refer to
Check indoor coil
"Check of indoor
thermistor. Refer
fan motor" on
to"Test point dia-
page 40.
gram and voltage"
on page 42~44.
Symptom Detect method
Detect Indoor coil/room tem-
perature thermistor short or
open circuit every 2 seconds
during operation.
When rotational frequency
feedback signal is not emit
during 12-second indoor fan
operation
Indoor unit doesn't
receive the signal from
remote controller.
Also, OPERATION INDI-
CATOR lamp doesn't
flash, when the EMER-
GENCY OPERATION
switch is pressed.
Refer to "Check of
C
indoor electronic control
P.C. board" on page 41.
Check room temperature
A
thermistor. Refer to"Test
point diagram and volt-
age" on page 42~44.
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.