Mitsubishi Electric MSZ-FD09NA Service Manual page 24

2. Indoor unit failure mode table
Abnormal point
POWER
(Failure mode)
Not lighted Normal
1-time fl ash every Room temperature
0.5-second thermistor
2-time fl ash Indoor coil thermis-
2.5-second OFF tor
3-time fl ash
Serial signal
2.5-second OFF
11-time fl ash
Indoor fan motor
2.5-second OFF
12-time fl ash Indoor control
2.5-second OFF system
NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (9-4.).
Condition
—
The room temperature thermistor short or open
circuit is detected every 8 seconds during op-
eration.
The indoor coil thermistor short or open circuit
is detected every 8 seconds during operation.
The serial signal from outdoor unit is not re-
ceived for a maximum of 6 minutes.
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.
24
Correspondence
—
Refer to the characteristics of the room temperature
thermistor (9-7.).
Refer to the characteristics of the main indoor coil
thermistor, the sub indoor coil thermistor (9-7.).
Refer to 9-6. "How to check miswiring and serial
signal error".
Refer to 9-6. "Check of indoor fan motor".
Replace the indoor electronic control P.C. board.