Mitsubishi Electric MS-A09WA Service Manual page 12

2. Indoor unit failure mode table
Left lamp of OPERATION
INDICATOR lamp
Not lighted
Room temperature
1-time flash
thermistor
every 0.5-second
2-time flash
Indoor coil thermistor
2.5-second OFF
11-time flash
Indoor fan motor
2.5-second OFF
12-time flash
Indoor control system
2.5-second OFF
NOTE : Blinking patterns of this mode differ from the ones of Troubleshooting check table (8-4.).
Abnormal point
(Failure mode)
Normal
The room temperature thermistor short or
open circuit is detected every 8 seconds
during operation.
The indoor coil thermistor short or open
circuit is detected every 8 seconds during
operation.
The rotational frequency feedback signal is
not emit during the 12-seconds the indoor fan
operation.
It cannot properly read data in the nonvolatile
memory of the indoor electronic control P.C.
board.
Detection method
–
Refer to the characteristics of the room
temperature thermistor (8-7.).
Refer to the characteristics of the main
indoor coil thermistor, the sub indoor coil
thermistor (8-7.).
Refer to 8-6.A "Check of indoor fan
motor".
Replace the indoor electronic control
P.C. board.
12
Correspondence
–