Mitsubishi Electric MSZ-GC22VA Service Manual page 16

2. Indoor unit failure mode table
Upper 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
3-time flash
Serial signal
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 (10-4.).
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 serial signal from outdoor unit is
not received for 6 minutes.
The rotational frequency feedback signal is
not sent out for 12-seconds after indoor fan
motor is opeated.
It cannot properly read data in the
nonvolatile memory of the indoor electronic
control P.C. board.
Condition
—
Refer to the characteristics of the room
temperature thermistor (10-7.).
Refer to the characteristics of the main
indoor coil thermistor, the sub indoor coil
thermistor (10-7.).
Refer to 10-6.D "How to check mis-wiring
and serial signal error".
Refer to 10-6.A "Check of indoor fan
motor".
Replace the indoor electronic control
P.C. board.
16
Correspondence
—