Mitsubishi Electric M Series Installation Manual page 102

MITSUBISHI ELECTRIC / DIAGNOSTIC
FAILURE MODE RECALL M SERIES
THE UPPER LAMP
OF OPERATION INDICATOR LAMP
Not lighted
1-time flash every 0.5-second
2-time flash every 2.5-second OFF
3-time flash every 2.5-second OFF
11-time flash every 2.5-second OFF
12-time flash every 2.5-second OFF
100
- INDOOR UNIT - MONOSPLIT
ABNORMAL POINT
(FAILURE MODE)
Normal
Room temperature thermistor
Indoor coil thermistor
Serial signal
Indoor fan motor
Indoor control system
CONDITION
-
The room temperature thermistor short
oropen circuit is detected every 8
seconds during operation.
The indoor coil thermistor short or open
circuitis detected every 8 seconds during
operation.
The serial signal from outdoor unit is not
received 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.
REMEDY
-
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. "How to check miswiring
and serial signal error".
Refer to 10-6. "Check of indoor fan
motor".
Replace the indoor electronic control
P.C. board.