Mitsubishi Electric MSZ-FH09NA Service Manualce Manual page 22

2. Indoor unit failure mode table
The left lamp of
Abnormal point
the OPERATION
(Failure mode)
INDICATOR 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 (9-4.).
3. Operation check on i-see SENSOR
While recalling the failure details, set the temperature to 66°F (19°C) to perform the simple check on the i-see SENSOR.
Place your hand over the i-see SENSOR, and the buzzer will beep at 1 second intervals. (Normal detection temperature
range is 93 to 102°F (34 to 39°C).)
If the buzzer does not beep, check for disconnection of the connectors.
Set the temperature to 73°F (23°C) to exit the simple check mode on the i-see SENSOR.
The left lamp of
Abnormal point
the OPERATION
(Failure mode)
INDICATOR lamp
6-time fl ash i-see SENSOR
OBH683B
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 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.
Condition
Poor contact in i-see SENSOR wiring
Failure in loading corrected data of i-see
SENSOR
22
Remedy
—
Refer to the characteristics of the room temperature
thermistor (9-7.).
Refer to the characteristics of the main indoor coil ther-
mistor, 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.
Remedy
Check for disconnection of the connectors.