20
2. Indoor unit failure mode table
Left lamp of OP-
ERATION INDICA-
TOR lamp
Abnormal point
(Failure mode)
Condition
Remedy
Not lighted
Normal
—
—
1-time f ash every
0.5-second
Room temperature
thermistor
The room temperature thermistor short or
open circuit is detected every 8 seconds dur-
ing operation.
Refer to the characteristics of the room temperature
thermistor (10-7.).
2-time f ash
2.5-second OFF
Indoor coil
thermistor
The indoor coil thermistor short or open circuit
is detected every 8 seconds during operation.
Refer to the characteristics of the main indoor coil ther-
mistor, the sub indoor coil thermistor (10-7.).
3-time f ash
2.5-second OFF
Serial signal
The serial signal from outdoor unit is not re-
ceived for a maximum of 6 minutes.
Refer to 10-6. "How to check miswiring and serial
signal error".
11-time f ash
2.5-second OFF
Indoor fan motor
The rotational frequency feedback signal is not
emitted during the 12 seconds the indoor fan
operation.
Refer to 10-6. "Check of indoor fan motor".
12-time f ash
2.5-second OFF
Indoor control
system
It cannot properly read data in the nonvolatile
memory of the indoor electronic control P.C.
board.
Replace the indoor electronic control P.C. board.
NOTE
: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-4.).
OBH555D
