Fujitsu Cassette not running

[Climateman]

We recently installed several Fujitsu cassettes. All run ok except one. It is showing a comms fault. We checked the cable with a meter, ok. We also disconnected our condensate pump.

Climate Centers AC tech said it must be outdoor board, changed it but fault still there. They then said it must be indoor board, changed it, fault still there. They suggested not wiring the neutral through the isolator but direct, did this, fault still there. (we had this fault on another Fujitsu unit and wiring the neutral directly eliminated the fault).

We're stuck, they're stuck. Can anyone help. Model numbers are, Cassette AUY12MAKL, outdoor unit AOY12MAKL

[ConDor]

Its been awhile since i have seen a fujitsu (thank god for that, they a way too advanced). But i seem too recall we had a lot of problems with the dipswitch settings. Specially the wired connection between controller and evaporator. There where a type fault in the manual.

[sinewave]

I take it you've checked the obvious like is the polarity of the interconecting cable right?

Fujitsu's like to start with the Neutral then the Phase then control core/s. Where as other Manuf's like to start with the Phase first.

It's quite easy to transpose the L & N etc etc.

Double check all this before condeming PCB's etc

[LRAC]

Are you running the comms through an isolator sometimes the signal can get weakened through the isolator and bring up a fault.

If so remove wiring from isolator and wire direct between indoor and outdoor. Please keep the mains on the isolator though.

Regards
Lrac

[markj]

Hi,

just try connecting the outdoor and indoor with some 4 or 5 core flex to elimate the interconnection wiring. I had this once withan old R22 unit that we re installed using FP200 as the inter connect. unit would not run etc.. turned out to be fauly cabling only showed up when we used a megger after to test , luck we had a spare core!

[marc5180]

i agree witn LRACs opinion, iv just come back from having 3 faulty units in london that were showing as a comms error.... i checked everything you probably did, pumps, boards, weather there were any nicks in the wires..everything i could think of. Finally i realised that the indoors had isolators in the interconnecting and that the signal wire had gone through the isolator. I removed the signal wire and crimped it on each of the units and the units came on almost straight away....i wouldnt have thought that this was likely but it did work. Hope it works for you

[Climateman]

Thanks everyone. There is no isolator on the comms cable. Actually we had a fault 2 weeks ago on a Fujitsu wall mount where it showed a comms fault until we removed the neutral from the mains isolator and wired direct.

Anyway, ConDor's idea about the dip switches sounds possible.

Part of the difficulty is that the unit is in an opticians consulting room and we have to book an appointment to get into the room. We're back on Monday and the Fujitsu tech guy will be available by phone. I'll let you know what it was (assuming we can get to the bottom of the problem)

[digi-finger]

Thanks everyone. There is no isolator on the comms cable. Actually we had a fault 2 weeks ago on a Fujitsu wall mount where it showed a comms fault until we removed the neutral from the mains isolator and wired direct.

Anyway, ConDor's idea about the dip switches sounds possible.

Part of the difficulty is that the unit is in an opticians consulting room and we have to book an appointment to get into the room. We're back on Monday and the Fujitsu tech guy will be available by phone. I'll let you know what it was (assuming we can get to the bottom of the problem)

what is the specific fault code, recently had several problems like this usually involving faulty outdoor boards check control voltage.

[Dr._Fleck]

We had this exact fault on a fujitsu cassette, we tried everything mentioned above. It turned out the wires on the indoor unit connector block had been put on in the factory the wrong way round. Flippin numpties!
Check the colours of the wires against the other units

[Climateman]

I think my engineer has checked wiring with diagrams. Fuj tech got us to check the capacitor in the outdoor unit. It was ok too, he gave up after that & told us to go back to Climate Centers.

We'll see what their position is. Must check control voltage

[monkey spanners]

We had one today with communication error, turned out to be the float switch. unplugged it and it work ok. would work on everything but cooling before unplugging float swittch.

Jon

[cruzeiros]

Sorry because is not at the subject...

I have a Fujitsu casette and is icing up the interior unit with no fault and no lost of *****. (410A). Any advice ?!?!?!?!
Thanks

[Dr._Fleck]

These are the things i'd be looking for:

1. short of refrigerant? (by far favourite)
2. is the indoor fan always on?
3. is the outdoor fan running normally?
4. are the filters blocked?
5. has anybody else been working on it recently? (it could have the wrong refrigerant in it.)

Erm.. can't think of any more but check the back pressure and read off the evaporating temperature on your gauges, it should really be above 0 degrees c... Perhaps a bit below, but not loads!

[Andy W]

Is it sized up correctly, controller set correctly, controller able to switch the outside unit off, which probe is sensing actual temperature, I went to an LG that a mate had installed once and the hard wired remote controller was set to use the onboard thermistor of the controller and the controller was fitted to a wall above a radiator.

[ozairman]

We recently installed several Fujitsu cassettes. All run ok except one. It is showing a comms fault. We checked the cable with a meter, ok. We also disconnected our condensate pump.

We're stuck, they're stuck. Can anyone help. Model numbers are, Cassette AUY12MAKL, outdoor unit AOY12MAKL

They are not valid Fujitsu model numbers, are you sure it is not AUY12LBAB AOY12LMAKL??
If the system is the AOY12LMAKL then what is the actual error code/flash pattern on indoor unit?
Again if the system is AOY12LMAKL does the outdoor unit actually power up and energise when power is applied? Do you hear the power relay click on power up and the Electronic expansion valve energise? if so then ODU should be alive.
Does the indoor fan run?

Again if unit is AOY12LMAKL have you tried to measure the communication signal between IDU and ODU at all. If it is a communications error then you need to establish whether it is the IDU or ODU that is not communicating and then work out WHY

Cheers from downunder

[Climateman]

They might not be valid Fujitsu model numbers in Aus but they are in UK.

Latest update - Fujitsu sent their tech guy. We spent an hour in the rain checking wiring and swopping small PCB from one of the other systems we fitted.

He eventually traced fault to factory wiring in indoor unit. 2 wires on wrong terminals causing comms fault.

Well done that man! Now I can get paid. Thanks for all the input guys.

[ozairman]

No drama's climateman,
I know they weren't aussie numbers which have a T in place of the Y in the code before the digits. Those numbers I was quoting in the last post were for FG euro product which is what I would expect you guys to be using in the UK.

Did you take any note of which wires were crossed over, was it on the terminal block to the OU connections? Just remember on FG stuff Black=active, White=neutral and Red=signal inside the actual unit. A lot of sparkies over here in Oz can't seem to get their head around that and often wire units up with 240V active to the wires with the Red and Black on them inside the machine and stand there scratching their heads wondering why it doesn't work, especially when the terminals are always marked L N and 3!

[Dr._Fleck]

We had this exact fault on a fujitsu cassette, we tried everything mentioned above. It turned out the wires on the indoor unit connector block had been put on in the factory the wrong way round. Flippin numpties!
Check the colours of the wires against the other units

What did i tell you?

Stick with the Doctor and you'll be ok... Entering smug mode

[borodave1973]

Ignore my posts should have read both pages!

[acgibo]

Hello
Dont know if you have sorted this yet, but heres an idea for you antway...
Now it seems far out but try it
Disconnect the compressor and try it then. i had a unit the other week that was giving me a comms fault code. spent hours on the phone to techs...totally confused them until i eventually disconnected the comp' and what do you know the fault cleared!!!!!!!!!!!!!! no explanation as to why or how but it worked.
good luck

[Climateman]

Was it a Fujitsu?

ozairman, don't know which wires were problem. Tech guy had covers back on & we had to clear room. Must e-mail him & find out.