Daikin U4

[fridge doctor]

Guys I know this has been covered before, there was a thread earlier this year but the content just doesn't apply... First and foremost U4 is described as a comms error between INDOOR UNITS... Note NOT indoor/outdoor. So how can this show as a fault code on a single split having no connection to other indoors? Also, the previous poster had a problem with continual running of the outdoor and icing of the indoor which would happen naturally, and Paul suggested crossed wiring etc.. But I have no such problem. Nothing runs. U4 is a crap code it is meaningless, where do I start guys ?

Trevor... Frustrated with Daikin pass the buck attitude

[Chunk]

Are you sure its not E4 not U4,e4 will hold the condensing unit off(hp switch activation)

Just a lame guess.

[The Viking]

Well...

Had you provided a model number, I would have posted the manual for it.

Never mind.

Good luck.

[Temprite]

Is the green led flashing on the outdoor board?

[fridge doctor]

Thanks once again everyone for your contributions... Returned to the job today and got a result.

For the general good of all of us therefore, I post my findings..

System : Daikin wall split .. outdoor REY40GA7V1. Estimate 12/18K Btu.

Symptom : Turn on, green lamp stable, louvre opens, no further action... 20 seconds... green lamp flashes regular beat.

Diagnosis by a process of 3 hours on site elimination :

Outdoor board at fault.... no question.

Thanks again

Trevor