Mitsubishi Heavy Industries FDTCVA SERIES Technical Manual page 249

Indoor unit
Red LED 3 time flash
Keeps flashing
Green LED
Is the
wiring for remote
controller connected
correctly?
Approximately
10 ~ 11 V between
X and Z.
Remove the remote
controller wiring temporarily.
Remeasure
between X~Z.
10~11V.
Is the voltage
between CnW8
12V?
Replace the indoor
unit control PCB.
Outdoor unit
Red LED Stays OFF
Keeps flashing
Green LED
NO
Modify the connection.
OK
(1)
YES
Reset the power supply.
Note (1) Z is GND.
NO
YES
YES
Short circuit of the wiring for the remote controller.
Remote controller defect.
NO
(2)
NO
Check the
-
CnW5-8 harness.
Note (2) is GND.
YES
Exchange the harness.
Normal?
Maltifunction by
accidental noise
OK
Replace the indoor unit power
supply PCB.
NG
248
- -
NO
Remote controller wire
disconnection?
Remote controller defect.
YES
Only case of FDT