View Full Version : Fujitsu VRF

03-10-2016, 09:44 AM
I have been to a job site today to look at a Fujitsu AJYA54LCLR system.
It has 3 indoors connected, 2 ducted units and a wall system.
The customer reported flashing lights on the remote sensors.
Operation light is continually flashing, then the other 2 lights come on for 1 flash, then the green light(timer) flashes another 4 times.
I can't find any information on this system.
Have tried a power reset, and checked all the outdoor sensors.
The only one that looks a bit dodgy is the discharge sensor, but saying that, I don't know what the resistance should be.
After i plugged all the sensors back in, the system ran for an hour on heating, But stopped again with the same sequence of flashing lights. There are 6 leds on the outdoor board, but none of these lit up at all.
Any ideas?



03-10-2016, 08:41 PM
Hi Martin.

That's a J-Series VRF showing comms error.
LED 1 outdoors should always be lit or flashing with in error. From that looks like outdoor controller PCB not alive.

Outdoor wiring looks tricky but they are quite straight forward.

Power comes in through the filter PCB, out to the diode bridge via a relay/posistor combo.
AC into diode bridge, 300V DC out to ACTPM.
Boosted DC to IPM and also to main PCB to liven it up.

Idea is on power up current flows through posistor, if something is taking too much current then posistor goes open circuit and nothing happens until you fix it. If it's alright the main PCB turns the relay on which bypasses the posistor.

Best to check for the obvious (also fuse on main PCB), power down and disconnect circuit, fire up and add each section in turn (power on/off as required) until you find what part is causing posistor to open. Once you find what board is an issue remember it might be fine but a component plugged into it could be faulty and shutting out down.
Say you find the ACTPM faulty you wont be able to prove any further PCB errors until that part has been changed. Have to rely on resistance/diode test for further testing.
Some top bloke did an inverter testing guide which you should find on this site which might help. Do the normal compressor tests.

Indoor boards have a little 3.15A fuse which can blow for no obvious reason (power surge?), worth bearing in mind.


Edit: Found a manual, not a great help but has a few nuggets,

04-10-2016, 04:44 AM
Thanks Andy, What i don't understand is, the thing ran on heating for an hour after i put all the sensors back in with no problems. Then after an hour it stopped and started flashing a sequence of lights on the indoor receiver, with no fault lights on the outdoor at all. Fujitsu have sent me an error list for this system, but the sequence of lights is not on there?

04-10-2016, 05:53 PM
Hi Martin,

I've emailed part of the service manual. Whole lot was too big so just got the important part and the lights are on there too.
Sounds like an intermittent error then, always the best...
If not too much trouble, worth bypassing any indoor isolators and pumps coming off the interconnect. Shouldn't be the issue here but has been known in the past to cause comms errors. The outdoor LED's can be hard to see so are you double certain none are on/flashing. Heard people roll up a bit of paper and look down this, bit like a peeping Tom, not that I'd know anything about that.

13-10-2016, 10:25 AM
Hi Andy

Thanks for the email, a lot more info than Fujitsu came up with. I test ran the system on heating for an hour, then test ran on cooling for an hour, everything worked ok. I see what you mean about the leds being hard to see, as you can imagine the sun is pretty intense here and makes them almost invisible. I guess we will see how it performs during summer.