Fujitsu Split Unt Wallmount Inverter 2.5HP

[rashVRF]

Dear All,

I have checked out this split unit, it is a ASAA24JCC
A 2.5HP INVERTER WALLMOUNT.

It has been newly installed few months back, but hardly used as the house is being renovated etc.
when the unit is turned on, the unit just blinks 2 times - timer LED

That means serial reverse transfer error, ussualy a problem with the PCBs indoor or outdoor, or supply to the PCBs.

I have checked all, everything seems to be fine.
Checkd the Outdoor fan, expansion valve, PCBs replaced yet the same blinks!

Any idea what could it be ? Do you think the installation not done correctly as in vacuuming and gassing up ?

[install monkey]

check ur interconnecting cable-especially on the indoor spur- ensure nothing is crossed otherwise
sales@fgeurofred.co.ukService & Warranty Enquiries: service@fgeurofred.co.uk
FG Eurofred Limited (Sales Office)
Unit 150
Centennial Park
Centennial Avenue
Elstree
Hertfordshire
WD6 3SG
England
Phone: +44 (0)20 8731 3450

[r.bartlett]

check ur interconnecting cable-especially on the indoor spur- ensure nothing is crossed otherwise
sales@fgeurofred.co.ukService & Warranty Enquiries: service@fgeurofred.co.uk
FG Eurofred Limited (Sales Office)
Unit 150
Centennial Park
Centennial Avenue
Elstree
Hertfordshire
WD6 3SG
England
Phone: +44 (0)20 8731 3450

That's a real handy address for someone in Malaysia

[install monkey]

nothing like a long distance technical helpline to put u on hold for a while!!

That's a real handy address for someone in Malaysia

[r.bartlett]

nothing like a long distance technical helpline to put u on hold for a while!!

i guess it's just reversing the trend...

[rashVRF]

i guess it's just reversing the trend...

LOL.... reversin the trend...!
well I'd check the bridge wires linkin indoor / outdoor already...

I was wondering if the pipes were not vacuumd proper, cud it cause such probs for inverter units...

[Tayters]

check ur interconnecting cable-especially on the indoor spur- ensure nothing is crossed otherwise

An important point made by there. If in doubt wire direct from the outdoor to indoor so you don't go through any isolators or pump high level switches.

As a rule the units should be wired direct to each other. Depending on your region and interpretation of the rules, if an isolator is used indoors then it shouldn't switch the comms cable as the poles in the switch can sometimes have a bad enough connection to disrupt the signal. As the comms signal is referenced to neutral then the same applies to the negative cable as well.

In practice I've only ever seen the comms connected straight through and live and neutral switched. Seems to work fine but important to bear the neutral cable in mind when checking out comms faults on splits.

Best avoid using the high level switch on pumps to break the comms signal. Either use it to switch a third party alarm or if the switch and it's cabling is capable of taking the current, wire the 240V feed to the indoor unit through it instead but make sure it's well marked up on the indoor unit to save any confusion if the switch breaks contact.

Cheers,
Andy.

[Tayters]

Serial reverse error means indoor unit getting no comms from outdoor unit.

This is normally due to the outdoor not powering up fully due to faulty PCB or outdoor unit electrical load such as fan motor, 4 way valve, ACTPM etc. This can be confirmed by no comms voltage (interconnect neutral and 3 50-100V DC)

Look for the 2 orange wires if your model has them listed that go to the Posistor. This is an anti-surge device that will open up if something is taking to much current. In normal operation it will pass a small current, PCB's will liven up and switch a relay across the posistor so more current will flow.

Power the unit down, wait at least 2 minutes to allow the capacitors to discharge (measure voltage across P and N on inverter board or voltage between red and black wires on fan motor. Otherwise you'll unplug the fan motor and it will spark across and blow the PCB and maybe the fan motor as well. Yep - done it myself!

Disconnect fan, eev, 4 way valve, power back up, see if you have comms voltage between neutral and terminal 3 of interconnect 50-100V AC.
If so power down, wait for capacitors to discharge, plug 1 component back and redo the procedure.

To test the fan motor with it unplugged measure resistance between black and red (340V DC input) when unplugged and between black and the wire next to it (15v DC to power internal PCB of motor). If they read low resistance then motor down.

Normal problem is fan motor faulty causing PCB not to liven up and initiate comms.

I don't think your model has the orange wires for the posistor as it's built onto the board but you'll have to check. If the components don't provide any clues then there maybe another fault with one of the other outdoor PCB's if they are seperate. If so let me knopw and I'll find a diagram if possible to see which way to go.

Cheers,
Andy.

[rashVRF]

Serial reverse error means indoor unit getting no comms from outdoor unit.

This is normally due to the outdoor not powering up fully due to faulty PCB or outdoor unit electrical load such as fan motor, 4 way valve, ACTPM etc. This can be confirmed by no comms voltage (interconnect neutral and 3 50-100V DC)
~ When you say interconnect neutral, you mean using a multimeter/tester to check values, correct ?


Look for the 2 orange wires if your model has them listed that go to the Posistor. This is an anti-surge device that will open up if something is taking to much current. In normal operation it will pass a small current, PCB's will liven up and switch a relay across the posistor so more current will flow.
~ I believe my model does have the two orange wires, the posistor could be built on the pcb it self, (a wiring diagram will be shown)

Power the unit down, wait at least 2 minutes to allow the capacitors to discharge (measure voltage across P and N on inverter board or voltage between red and black wires on fan motor. Otherwise you'll unplug the fan motor and it will spark across and blow the PCB and maybe the fan motor as well. Yep - done it myself!
~ P is Live is that correct? So measure across Live and Neutral to determine if supply is shut before unpluggin the fan motor.


Disconnect fan, eev, 4 way valve, power back up, see if you have comms voltage between neutral and terminal 3 of interconnect 50-100V AC.
If so power down, wait for capacitors to discharge, plug 1 component back and redo the procedure.
~ Ok i understand this part, remove components and check without them and then start pluggin component back 1 at a time and re check, the value from neutral and 3 on multimeter should show a swing value usually between 30V to 130V is that right ?


To test the fan motor with it unplugged measure resistance between black and red (340V DC input) when unplugged and between black and the wire next to it (15v DC to power internal PCB of motor). If they read low resistance then motor down.
~ from the service manual i have the resistance value on testing fan motor. I wil also paste a copy of this info.

Normal problem is fan motor faulty causing PCB not to liven up and initiate comms.

I don't think your model has the orange wires for the posistor as it's built onto the board but you'll have to check. If the components don't provide any clues then there maybe another fault with one of the other outdoor PCB's if they are seperate. If so let me knopw and I'll find a diagram if possible to see which way to go.
~ I have only one outdoor PCB in this model, Let me get the diagrams. Will repost in an hour.
Thanks alot bud.


Cheers,
Andy.

Firstly, thanks andy...thats was rather detail and I am going to give that a shot since Im outta ideas.
my replies are in quote coloured blue~

[rashVRF]

cirdia0001.jpg

SERIAL SIGNAL.jpg

[Tayters]

Serial reverse error means indoor unit getting no comms from outdoor unit.

This is normally due to the outdoor not powering up fully due to faulty PCB or outdoor unit electrical load such as fan motor, 4 way valve, ACTPM etc. This can be confirmed by no comms voltage (interconnect neutral and 3 50-100V DC)
~ When you say interconnect neutral, you mean using a multimeter/tester to check values, correct ?
~ Yes, use a multimeter. The neutral and comms on the interconnect (Terminal 2 - I've checked a diagram now, terminal 2 is neutral, comms is terminal 3)

Look for the 2 orange wires if your model has them listed that go to the Posistor. This is an anti-surge device that will open up if something is taking to much current. In normal operation it will pass a small current, PCB's will liven up and switch a relay across the posistor so more current will flow.
~ I believe my model does have the two orange wires, the posistor could be built on the pcb it self, (a wiring diagram will be shown)
~I've checked a diagram and the posistor is part of the board and on the neutral side. On yours there is 1 orange wire which carries the neutral from the last part of the PCB (Bridge Rectifier) on W6, then hops across on the orange wire to W5, into the posistor then to neutral. It's near the centre of the PCB slightly away from the heatsink side of things. The PCB is upside down so easy to check voltage and things are labled up quite well. If you can see it, the posistor is marked as R1 on the soldered side of the board.

Power the unit down, wait at least 2 minutes to allow the capacitors to discharge (measure voltage apcross P and N on inverter board or voltage between red and black wires on fan motor. Otherwise you'll unplug the fan motor and it will spark across and blow the PCB and maybe the fan motor as well. Yep - done it myself!
~ P is Live is that correct? So measure across Live and Neutral to determine if supply is shut before unpluggin the fan motor.
~You will need to check on the DC part of the circuit. P is a 340V DC feed. It comes from the AC supply being rectified then used to power inverter and fan motor. On the PCB, look where the compressor wires go to. As these go to the PCB the connect to U, V and W on the inverter chip. Either side of these joints are the P and N - Positive and Negative 340V DC supply.

Disconnect fan, eev, 4 way valve, power back up, see if you have comms voltage between neutral and terminal 3 of interconnect 50-100V AC.
If so power down, wait for capacitors to discharge, plug 1 component back and redo the procedure.
~ Ok i understand this part, remove components and check without them and then start pluggin component back 1 at a time and re check, the value from neutral and 3 on multimeter should show a swing value usually between 30V to 130V is that right ?
~That's it!
To test the fan motor with it unplugged measure resistance between black and red (340V DC input) when unplugged and between black and the wire next to it (15v DC to power internal PCB of motor). If they read low resistance then motor down.
~ from the service manual i have the resistance value on testing fan motor. I wil also paste a copy of this info.
~The motors have a PCB built into them. They take a 340V DC supply and use this to work their own inverter circuit on the internal PCB. There is also a 15V DC supply to power the PCB, a signal speed input and output. A fan motor from the future!
Normal problem is fan motor faulty causing PCB not to liven up and initiate comms.

I don't think your model has the orange wires for the posistor as it's built onto the board but you'll have to check. If the components don't provide any clues then there maybe another fault with one of the other outdoor PCB's if they are seperate. If so let me knopw and I'll find a diagram if possible to see which way to go.
~ I have only one outdoor PCB in this model, Let me get the diagrams. Will repost in an hour.
Thanks alot bud.




Firstly, thanks andy...thats was rather detail and I am going to give that a shot since Im outta ideas.
my replies are in quote coloured blue~

I've pasted and added the red bits.

Hope it helps!

Cheers,
Andy.

[rashVRF]

I've pasted and added the red bits.

Hope it helps!

Cheers,
Andy.

Im going to give this diagnose method a shot today.... will update after.

cheeers bud!

[rashVRF]

I've pasted and added the red bits.

Hope it helps!

Cheers,
Andy.

Ive tried it, Measure the N and 3 while everything is plugged in, i got a readin of 30V to 70V AC on multimeter.
then first thing i tried was with the outdoor fan motor plugged out, turned on power and just before i tried it , the unit started up... the indoor was on "test run" i guess it took about 2 ~ 3 mins before i came with the multimeter and realised the outdoor compressor started running...

I still measured it with the outdoor fan motor unplugged, and got swing value approx almostttt the same... hmmm... anyhow, im quite certain the outdoor fan motor needs a replacing and maybe the outdoor pcb (incase the terminals or dv volt part to outdoor fan motor is bust)

how was my judgement ? rookie enough ? hehe..

[Tayters]

If the unit was powered off and on from the main isolator before the testing this would have cleared the fault code assuming worse case it was intermittant and had just stayed out on the fault code.
If it faulted straight away when power was turned back on (I guess it was as in the first post you say the PCB was replaced) but only fired into life once the fan motor was disconnected then it's a fair chance that is where your fault lies.

If you fancy testing the fan motor then there a couple of tests you can do from this thread: http://www.refrigeration-engineer.com/forums/showthread.php?15069-Fujitsu-General-Fault&highlight=posistor post 59. Credit goes to Ozairman

Also if you search 'posistor' you will find some info on them on this site which might explain further the PCB operation. Took me a while to digest it all but makes sense and is easier to troubleshoot than you might imagine.

Cheers,
Andy (still a Rookie myself!)

[install monkey]

should be a test button on the remote- run in cooling for as long as possible to get the room temp as low as possible.
set for 30heat then push the recessed test button-and hopefully it should run