Mitsubishi Electric MSC-07RV Service Manual page 123

13-2. Instruction of troubleshooting
<MU-07/09/12RV,MUH-07/09/12RV,MUX-10/18/24RV> (Refer to page 124 for MXZ-18/32RV)
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 133
and 134.
Refer to
E
"How to check
mis-wiring and
signal error
(when outdoor unit
doesn't work)"
on page 135. 1
Indoor unit doesn't
receive the signal
from remote
controller.
Refer to
B
"Check of remote
controller and
receiver P.C. board"
on page 132.
1-time flash
D
Cause:indoor/outdoor unit
connecting
Trouble of mis-wiring
(
Trouble of the serial signal
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 tempera-
ture/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 132.
gram and voltage"
on page 142.
1<The case of the trouble of the serial signal>
When the power is turned off and then turned on again, the indi-
cation shows "the trouble of mis-wiring."
123
Indoor unit doesn't
receive the signal from
remote controller.
Also, OPERATION INDI-
CATOR lamp doesn't
light, when the EMER-
GENCY OPERATION
switch is pressed.
Refer to "Check of
C
indoor electronic control
P.C. board" on page 133.
6-time flash
2.5-second OFF
Cause:outdoor unit
6-time-Check the defrost
thermistor
A Check room temperature
thermistor. Refer to"Test
point diagram and volt-
age" on page 142.