Fujitsu split problem

[Keza]

Hi Guys,

I have a Fujitsu split system that only seems to fault out when I'm not on site.
Model: ASTG09LVCC

When I am on site the unit runs fine. The compressor and the outdoor fan run, the indoor fan runs and the unit cools.

The owner has caught it on camera flashing its fault:
Operation light: 9 times
Timer Light: 9 Times
Economy light: Continuously

All I could find is something indicating 4 Way valve error. I think this seems odd. Either I have the wrong info or the 4 way valve has an issue. But how would that throw up a fault code, all it has is a coil. And why would it run fine for hours?

Anyone service a lot of Fujitsu units? Help very much appreciated.

Thanks,
Keza

[Tayters]

That's the right code. It's saying the indoor coil probe is 10*C different than the air probe the wrong way.

So could point to dodgy probe, sticky 4WV, faulty coil or PCB.
Seem to recall something about outdoor units getting air from another unit getting blown onto them causing similar issue. Doesn't quite fit in with the error judgement as manual says it is looking at indoor probes but it's lodged in my brain from somewhere. Could be wrong but worth bearing in mind.

Cheers,
Andy.

[Keza]

Thanks Tayters, I called Fujitsu tech support and they pointed me straight to replacing the indoor pipe and air thermistors. They are attached to the same plug.

Cheers