Fujitsu AOTR18LCC Fault Code

[ferret82]

Hi,

I have a AOTR18LCC A/C which has come up with a green light flashing twice then goes out. I have read though the threads on this website which have gotten me this far but i require more information.

When the indoor (I/U) unit starts up and after a delay the outdoor (O/U) does nothing with this fault but i did notice that the condensor fan wanted to work but couldnt.

I disconnected the Compressor and tested which gave 1 ohm across all winding and infinity to earth when meggered.

I disconnected the fan and started up but the same fault occuired so i disconnected the compressor (with fan reinstalled) and the fan ran for about 4 seconds then stopped. I measured the voltage at N&3 which was approx 110v at this time. This was not there when compressor was connected.

This is where the other threads got me too. I am trying to get a diode to do further testing but if anyone can give me more information on where to look next that would be great.

Also does anyone have and service manuals for fujitsu or a link on the net that i can get it from.

Also with the diode test I have tried to find a write up on the net but having no luck, does anyone have a link for this aswell? The other threads I have read are not that clear to me on how to test using the'diode check' method.

Thanks for your time

Cheers

Kayne

[nike123]

Green LED 2 times flashing mean indoor unit thermistor faulty/open.

Check timer LED flashing!

Check thermistors resistance (50kOhm at 25°C) and connection.
Timer led 2 flash:
Indoor temperature thermistor open / short
Timer led 2 flash:
Heat exchanger middle thermistor open / short

[ferret82]

Green LED 2 times flashing mean indoor unit thermistor faulty/open.

Check timer LED flashing!

Check thermistors resistance (50kOhm at 25°C) and connection.
Timer led 2 flash:
Indoor temperature thermistor open / short
Timer led 2 flash:
Heat exchanger middle thermistor open / short

Hi Nike123,

I dont believe that its the indoor unit as yesterday I replaced the outdoor unit and the indoor unit remained the same and the A/C was commissioned and is running well.
I now have the faulty O/U in the work shop and set up and the fault is now occuring on a new head unit. This is why I believe the problem is in the O/U.

I will have a look at what you said but dont think that this will fix the problem.



Thanks
Kayne

[nike123]

Hi Nike123,

I dont believe that its the indoor unit as yesterday I replaced the outdoor unit and the indoor unit remained the same and the A/C was commissioned and is running well.
I now have the faulty O/U in the work shop and set up and the fault is now occuring on a new head unit. This is why I believe the problem is in the O/U.

I will have a look at what you said but dont think that this will fix the problem.






Thanks
Kayne

Sorry, I misinterpreted your description of fault indication.

Green LED is timer LED and that mean serial reverse transfer error
at starting up operation.

At the start up, the indoor unit does not receive the signal for 10 consecutive seconds from the time when the power relay was ON.
>Permanent stop after 30 seconds.
[Diagnosis Point]
Check the indoor /outdoor cable connection (in order). If the cable wiring is not abnormal, measure the voltage of the outdoor
unit terminals and diagnose the defective location.

[ferret82]

I have been though that diagram that you posted and this woudl have been nice when i first started fault finding on this unit.

I dont understand the AC350-415 at NO DC Voltage terminal. Could you please explai a little more i have not wriing diagrams for this unit.

I really am suspecting that the board is faulty now this is the only thing that it could be as the wiring is fine the compressor is fine and the fan is fine.

Is there anything else i can test electricially to prove that the PCB is the problem.

Nike123 that diagram that you posted is this from a service manual? if so are you able to email it to me? or any information that you have on fujitsu units?

Thanks

Kayne

[nike123]

[QUOTE]

I have been though that diagram that you posted and this woudl have been nice when i first started fault finding on this unit.

I dont understand the AC350-415 at NO DC Voltage terminal. Could you please explai a little more i have not wriing diagrams for this unit.

You should check for these voltages between POW GND and marked points.

I really am suspecting that the board is faulty now this is the only thing that it could be as the wiring is fine the compressor is fine and the fan is fine.

Is there anything else i can test electricially to prove that the PCB is the problem.

This test is sufficient!

Nike123 that diagram that you posted is this from a service manual? if so are you able to email it to me? or any information that you have on fujitsu units?

Thanks

Kayne

I cannot send you manuals because that is against Fujitsu policy.
Register with their representative and you could access documents, but they want to do that in hierarchical way. They are Japanese, you know!

[ferret82]

Thanks for that Nike123 I will have a look tomorrow. Unfortunately I dont work for an air conditioning company, I work on a oil rig in the desert in Australia where i am the electrician and Refrigeration Engineer. I have already asked Fujitsu for the manuals and they have said to continue to call them.

Thats ok though I dont mind posting threads on here to learn what others have done and found.

Thanks for all your help i will get back to you with more tommorrow.

One thing though i wont forgot how to get another one if it breaks.

Cheers

Kayne