Troubleshooting Check Table - Mitsubishi Electric MCFH-A12WV Service Manual

1. Troubleshooting check table

OPERATION
INDICATOR
lamp
Before taking measures, make sure that the symptom reappears, for accurate troubleshooting.
Self check table
Abnormal
NO.
point
0.5-second ON
Mis-wiring
or Serial
1
signal
0.5-second OFF
Indoor coil
2-time flash
thermistor
2
Room
tempera-
ture ther- 2.5-second OFF
mistor
4-time flash
Indoor
control
3
P.C.
board
6-time flash
Outdoor
4
thermistor
MCFH-
7-time flash
A24WV
MXZ type
5
Outdoor
control
P.C.
board
5-time flash
MXZ type
Outdoor
6
power
system
Operation Indicator
MXZ type
Operation
7
mode
Lighted
setting
Flashing
The indication is shown only when the indoor unit connects with the outdoor unit MXZ type.
Indication
2.5-second OFF
2.5-second OFF
2.5-second OFF
2.5-second OFF
2.5-second OFF
Symptom Detect method
Outdoor unit When serial signal stops for 4
does not run. to 5 seconds.
Detect Indoor coil/room tem-
Outdoor unit
perature thermistor short or
does not run.
open circuit every 8 seconds
during operation.
When it cannot properly read
Indoor unit data in the nonvolatile memory
does not run of the indoor control
P.C.board.
When the outdoor thermistors
Outdoor unit
short or open after the com-
does not run
pressor start-up.
When it cannot properly read
Outdoor unit data in the nonvolatile
does not run memory of the outdoor control
P.C.board.
When the compressor
operation is continuously
Outdoor unit three times interrupted by
does not run over current protection within
1 minute after start-up , it
stops operation.
When the operation mode of
each indoor unit is differently
Outdoor unit
set to COOL(includes DRY)
operates but
and HEAT at same time, the
indoor unit does
operation mode of indoor unit
not operate.
that has operated at first has
the priority.
13
Check point
Check wiring (visual check and conductiv-
ity check).
Check indoor electronic control
P.C.board.
Check deicer P.C. board.
Check electrical parts.
Check resistance of thermistor.
Reconnect connector.
Check indoor electronic control P.C.board.
Check the indoor control P.C. board.
Check deicer P.C. board.
Check resistance of thermistor.
Reconnect connector.
Refer to service manual OB337, OB331
or OB319.
Check the outdoor control P.C.board.
Refer to service manual OB337 or OB319.
Check the inverter output.
Check the compressor.
Refer to service manual OB319.
Unify the operation mode.
Refer to service manual OB319.