fujitsu asy9lsacw/aoy12lsac problems

[squires80]

Hi all,

I am new to the forum and am after some advice.

My uncle has the above split room air conditioner, and after calling out 3 local "fujitsu experts" none of which could resolve the problem, we have decided to have a go ourselves. We will either break it even more or repair it. He is a retired electrician and I am a plumber (although have no experience with air con).

The problem is the outdoor unit is showing no signs of life and the indoor unit lights flash.
operation light 0.1 sec blinking and timer light 0.5 sec 2 times which according to the manual is "Normal Serial Reverse Signal can not be received more than 10 secs."
What does that mean? PCB failure?

The unit has had a pcb failure in the past and was replaced under warranty, but that was a few years ago. Could there be a faulty component causing the pcb to fail?
Any input is appreciated

Thanks

Carl

[Tayters]

Hi Carl,

It means indoor can't see the outdoor. Make sure interconnect is fine and live + neutral all good. Power off for a couple of mins, power on, select cooling, see if indoor sends out 240V to outdoor and neutral to comms (terminal 3) 70-120V AC If 50 V then this is a bit low. When code is triggered I think the relay turns off so it will need powering off/on to reset.

Refering to the circuit diagram in the manual you need to make sure the outdoor is powered up properly. Heres the way it works...

240V into PCB on W1 and W2,
Through a thermal fuse the out on W5, W6 to diode bridge.
Out of diode bridge at 300ish V DC
Into ACTPM on red and black
Out of ACTPM at maybe a higher DC voltage (330V DC possibly), across capacitor and back into main PCB
This DC voltage T's off to feed circuit to produce lower control DC voltage and off to feed IPM on yellow and blue.

If your power to outdoor is fine then see if any of these voltages are there. If no output on W5 and W6 then thermal fuse probably open circuit due to a fault further down. Power off disconnect the beginning of the circuit and see if voltage is there when power up. Next plug one thing in at a time following the sequence and see if one component is causing the thermal fuse to open.
Sometimes the fuse takes a little while to reset just to warn you.

Cheers,
Andy.

Edit: Can't attach files here as too large so will email.
Similar thread here: http://www.refrigeration-engineer.com/forums/showthread.php?35313-Fujitsu-split-error-help&p=256729&highlight=#post256729

[squires80]

Hi Andy, thanks for the info, I wil try out your suggestions and let you know.

[squires80]

Hi,

So I've checked the wiring on external unit and I'm getting 230v across L-N and 70v N-terminal 3.
I'm not getting anything across W5-W6. I tried disconnecting all the components on the PCB and it still gave nothing.
I can't locate the thermal fuse on the board to check if it is open or closing. there are 2 other fuses on the board, I checked from L to each side of the fuses and it gives 230v.
Not sure where to go from here.

Thanks
Carl.

[Tayters]

Hi Carl,

If there is 240V across W1 and W2 and no 240V across W5 and W6 when rest of circuit forward of this point is disconnected then thermal fuse is goosed or poor neutral on the PCB (check voltage to earth to confirm) or maybe a poor joint on the 240V side of things.
The thermal fuse is labled R201 in the manual so look for that. It's normally a black plastic box like a relay. In fact the relay K101 will close when properly powered up to bypass the thermal fuse to allow more current to flow and this relay should be nearby.



there are 2 other fuses on the board, I checked from L to each side of the fuses and it gives 230v.


Do you mean from N to each side?
There are 3 fuses. One fuse is off the PCB's which is the 240V AC supply. The other 2 are on the controller PCB but these are on the DC part so will need removing and testing with an ohm meter or check to the neutral off the diode bridge or somewhere along the DC Neutral path.

Cheers,
Andy.

[squires80]

Hi,
So we've taken out the pcb and rigged up to a fly lead in my uncles workshop to try and trace where the signal drops off.
The voltage gets as far as the ACTPM, with the choke coil and capacitor disconnected we are getting 310vac across L1-L2 on the ACTPM, once the coil is reconnected the thermal fuse cuts out.
We measured the windings on the coil and it was giving 1K ohms, not sure if that means anything.

Thanks
Carl

[frank]

If you look at your model numbers, you have a mis-matched pair. You have a 9000btu indoor unit connected to a 12000btu outdoor unit.

[squires80]

that was a typo its the 12000btu model

[Tayters]

Hi Carl,

The choke coil will connect the + input to the rest of the ACTPM.
If the output of the ACTPM on the P and N1 terminals was disconnected then it looks like the ACTPM is faulty.

The choke coil is just that - a coil. Not sure of the resistance, always thought it was around a few ohms but have never tested one myself. Even so, if it was reading too high then I can't see how this would trip the thermal fuse. You could try meggering it (disconnected from the circuit) just to be sure it isn't shorting to earth.

What made the ACTPM go if the choke coil is fine?
Well if you had a BLDC fan motor this would be a suspect but yours is a normal PSC so nothing to do with it. It may be worth double checking the 2 fuses on the controller PCB, megger the compressor and check the Transistor PCB (http://www.refrigeration-engineer.com/forums/showthread.php?37273). Unlikely these have caused the fault though.
The only other culprit is the main PCB but i think the chances are slim of that.

Over here the ACTPM is around £80.


Cheers,
Andy.