Daikin U4 error code

[Minty]

Hi fellow members,

My first post, so please bear with me ...

I have a Daikin split system with 2 indoor wall-mounted units. One of the units works fine. The other has a flashing green LED when I turn on the power and the error code shows as U4 (Communication error between indoor unit and outdoor EBS unit).

I am due to call out an engineer, but would like some advice as to potential causes and if possible, some indication of how big a job it would be to fix.

Many thanks

[4sac]

Is it as simple as ones in heating ones in cooling mode?

[Minty]

Hi 4sac,
I've tried all combinations of temerature, mode, fan speed etc and nothing happens. The vent flaps don't move - nothing. All that happens is the green LED keeps flashing until I switch the whole unit off.

[leegally1983]

Hi mate is sounds like a indoor pcb fault but i would check the interconnecting wiring first no loose connections etc. its not a big job 2 hours work at the most pcb a couple of hundred pound

[Minty]

Thanks for the advice. I'll check the wiring first

[Krondor]

From my experience with those units (we worked only with 4 indoors system) it would probably be outdoor PCB fault. On the outdoor PCB there are 2 communication channels for both of the indoors. You can check on those terminals if they supply similar voltage to both indoors. If the signals are the same, it would be the indoor PCB, if not, outdoor PCB.

Again, from my experience its an outdoor PCB
Good luck!
(tell us later what happened)

[Minty]

Thanks Krondor. I'll get someoen to take a look in the next few weeks.