Mitsubishi Electric MSZ-SF25VE Service Manual page 20

2. Indoor unit failure mode table
The left lamp of
Abnormal point
OPERATION INDI-
(Failure mode)
CATOR lamp
Not lighted Normal
1-time fl ash every Room temperature
0.5-second thermistor
Indoor coil
2-time fl ash
2.5-second OFF
thermistor
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 (10-4.).
OBH600B
Condition
—
The room temperature thermistor short or
open circuit is detected every 8 seconds dur-
ing operation.
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
emitted for the 12 seconds after the indoor fan
motor is operated.
It cannot properly read data in the nonvolatile
memory of the indoor electronic control P.C.
board.
Refer to the characteristics of the room temperature
thermistor (10-7.).
Refer to the characteristics of the main indoor coil ther-
mistor, the sub indoor coil thermistor (10-7.).
Refer to 10-6.
signal error".
Refer to 10-6.
Replace the indoor electronic control P.C. board.
20
Remedy
—
"How to check miswiring and serial
"Check of indoor fan motor".