Fujitsu air con

I have 2x AOHA24LAT3 units each running 3 indoor air handlers (ASHA12LACM)

One unit ( all 3 air handlers) has the green 'timer' light blinking 3 times.
Please tell me what this error code means, and what can cause it?

I have changed the entire PCB assembly from the working outdoor unit into the faulty one but this has not solved the problem.
Worse news is that when I changed it back into the original working unit I now have the same error code (3x green) flashing on the previously working units!

Is there anything you can suggest to help?

Do you have any other flashingleds or just the 3x green led?

https://www.manualslib.com/manual/96...page=15#manual

nothing else flashing, though it has now changed to 2x flashing green. Fujitsu manual lists both of these as 'Comms failure'

Hi Dave.
Sounds like you had something faulty (fan motor, EEV short to earth etc) on the first unit which had now taken out the second PCB.
It's just the one PCB on those units?

No. 2 pcb's. one power the other control. but it was easier to remove the two together in the chassis and switch the whole lot as one unit rather that trying to remove just the pcb itself.

Sure, makes sense. They can be a bit of a fiddle to get out.
It's the control board then that's probably gone. The other is just mains in then back out via the filters so easy to check and heavy duty enough to last.
For a start you can check if any of the connections on the plug for the EEV coils are shorting to earth, check fan motor plug terminals to confirm no short between any pins, check any temperature probes not short to earth then finally megger the compressor to earth to confirm the windings not short to earth.
Basically check nothing shorting to earth. 🤣
Cheers,
Andy.

Many thanks Tayters. I will get on with those tests. Basically the same answer I got from Fujitsu, though I cant understand why there is no protection of the PCB from earth faults built in?! Shouldn't be difficult to have a fuse blow rather that the whole PCB! (they ain't cheap).
Now I need to decide whether to buy a new board for the second unit which did not have any fault before I stole its PCB for the faulty one? I don't want to keep chasing bad money with good, but i can't see a reason why a fresh PCB will not bring the second unit back to life. What do you think?

Also, do you know of any suppliers of rebuilt PCB?? Just a long shot!!

Quote:

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Originally Posted by daveharvey

Many thanks Tayters. I will get on with those tests. Basically the same answer I got from Fujitsu, though I cant understand why there is no protection of the PCB from earth faults built in?! Shouldn't be difficult to have a fuse blow rather that the whole PCB! (they ain't cheap).
Now I need to decide whether to buy a new board for the second unit which did not have any fault before I stole its PCB for the faulty one? I don't want to keep chasing bad money with good, but i can't see a reason why a fresh PCB will not bring the second unit back to life. What do you think?

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Hi Dave,
A new PCB for the second unit should be fine.
As for how weak they can be then agreed! I guess it's down to money but it would be nice if they were a bit better protected but let's not hold our breath.

I'm not sure about anywhere that might repair it. In the UK there's Electronics Repair & Refurbishment - Maxey Moverley. Not sure how prices work out though.

Cheers,
Andy.