Have installed Mitsubishi fdc125vn with 2 srk 60 wall mounts, had communication fault and eventually replaced signal wire and unit ran fine. Had bosses son to help run new cable in and he wired 1 to 3 and blew to pieces. Since then have had only indoor units working. Have replaced outdoor pcb and both indoor pcb as per Mitsubishis instructions. Now have indication that I have communication error, have checked wiring between indoor and outdoor (even replaced signal cable) but still no joy.
Mitsubishi says could be indoor or outdoor fans. How can I check if signal being sent from indoor units. If I disconnect one unit (a) I have no fault , outdoor light on pcb flashes as normal. No light on inverter board ? Bring back on/off system.