Mitsubishi Heavy Industries - FDC180HA outdoor, FDT180HA Indoor- The inside unit is installed on the ceiling. The unit is working great. However, water is leaking from the inside of the ceiling unit.

Could be a defective relay in the outside unit

According to an LG installation manual for the LMU540HV, if the flashing light is viewed on the indoor unit with the ceiling cassette light on the far right flashing 5 times, it is an error code meaning there is a communication error between indoor and outdoor units. I would start by making all indoor and the outdoor units have power. I would especially check to see that fuses or circuit breakers to the outdoor unit have not failed. Or check the outside disconnect to make sure it is working. Check with a volt meter to be sure you have 220 volts present to the outdoor unit. Also, if the 4 indoor units have emergency power off switches, make sure all 4 are turned on. Checking to see power is present both indoors and outdoors a good place to start. It the outdoor unit has power, there may be a relay that has failed or a power circuit board has failed that would cause it not to communicate.

Most likely, there has been an operational fault that has triggered a "lock out". This happens when either a mechanical or electrical component has failed, misreading, or if the system has lost refrigerant. You can try to reset the system (both indoor and outdoor units). That might restart it, but a repairman should be called to pinpoint the issue that caused the fault. There is a diagnostic procedure that can help with the diagnosis, but it involves opening the outdoor unit to read the LED's on the control board.

this is a large and heavy fan , make sure electric box in cieliing is rated for fan's a plain one will not safely support the bigger fans

To reset it, remove the power plug and then restart.

check your comm board you need to make sure both are set to the same settings

E39 Fault is thermister, Mitsubishi way of saying im not going to start because there is something wrong. Generlly it is compressor fault or short of gas. Im guessing if you turned the power out. Waited twenty seconds, turn it back on. Now if you go to the outdoor part. Wait exactly 3 mins. If you hear the compressor try to start and fail then it would more then likely be your compressor if you dont hear anything and the unit faults out it will either be a board or short of gas.

Either way If the unit is under five years old get a warrenty agent out to look at it.

Sorry I couldnt tell you for sure but MHI are very vague when it comes to fault codes

as an refrigeration engineer dealing whit them every day my advise is: mitsi heavy industry away much more reliable and better performing.

This is a signal fault between the indoor and outdoor first make sure the dip switches are set start with the unit closest to the condensor set as unit 1 then next unit as 2 and so on the dip switches are inside the indoor unit on the pc board if you check the manual it will tell you which swithes to set, if this wasnt done when the units where installed they would have never worked i would also check the signal wiring between the wallmount and the splitter box / bc box and make sure there isnt a loose connection when you have ruled this out id say more than likely it is a faulty indoor board on the wallmounted unt

Double check your wiring .if the indoor fan is not blowing then you either have an electrical issue OR bad blower motor .