Fuji Fault Code on indoor unit

[Tecnicool]

Hi Any one who can help me. I have a problem with a Fuji / Fujitsu Inverter heat pump. Outdoor unit model No AOY18LMAK2. Indoor Unit RMS-12LA & 3 X RMS-07LA. My Customer has complained that after she had there incoming power supply reconnected after some Building work on her property that the fault code on her indoo units has activated. Green light flashing fast. Red light flashing 5 times. I have checked the fault code list and it has listed Serial order transmission error. I have checked the obvious. Ie Power in 230V Correct to live and neutral and to earth. seems ok. But not convinced As there are two complete systems and they have both developed the same fault after reactivation of the power supply by the electric board. Could the fault be a non perfect earth or am I barking up the wrong tree. Any thought gratefully received.

[Yuri B.]

Hope you have re-checked the correctness of the connections and the earthing.

[Tecnicool]

Can A bad earth give this fault code.

[install monkey]

if theyve had a new main fitted- check the connections on the fuseboard-mainly the tightness of the neutral connection.
also check any outdoor isolators to see if theres water in them- if fitted.
could be just coincidence that the ac units failed at the same time.

[Tecnicool]

This system is fitted in Mallorca Spain. They don't know what a isolator is. I have never ever seen one fitted here. Though I have fiited many myself. I will check the neutral conection for tightness. I still have this sneaky suspicion that this is not a coinidence. But hey any thing can happen here. You should see some of the installs I come across.

[install monkey]

check out some of these pics
http://www.facebook.com/#!/groups/242344512480316/

This system is fitted in Mallorca Spain. They don't know what a isolator is. I have never ever seen one fitted here. Though I have fiited many myself. I will check the neutral conection for tightness. I still have this sneaky suspicion that this is not a coinidence. But hey any thing can happen here. You should see some of the installs I come across.

[Steven_AC]

New board fitted?? Perhaps Live and Neutral have been swapped in the electrical board????

[aircon50]

Hi Tecnicool.
I understand what you mean about 'Spanish' wiring - I'm in Tenerife!
Am I reading correctly - AOH18LMAK2 with 1 x 12LA(CM) and 3 x 07LA connected? The reason I ask is that this exterior unit should only have two interior units. Or do you have 2 x AOH18LMAK2 driving 4 interiors?
Operation LED Red 5 flashes, Timer LED ? flashes. Are all interior units displaying the same code?
According to my Error Code list for this model - if Op has 5 then Timer has 2, 3, 5, 6, 7, or 8 flashes, which all relate to exterior unit control error.
Is the LED at exterior unit flashing?
I recently had a 24LAT3 indicating CT error (5 x Op, 3 x Timer). On checking there was very little refrigerant in the system, so the compressor wasn't drawing enough current and threw up the error code.
Best of luck
Graham

[Tecnicool]

I have checked that the live incoming is correct and Neutral to.
With regards to the units. Yes there is two outdoor units. All four indoor units are displaying the same fault code.
Cheers.
Tecnicool.