Saunier Duval Problem

We have a problem with a Saunier Duval air-con unit in one of our holiday let properties. Three engineers have been out to look at the problem but keep referring us to saunier Duval themselves saying they cant repair. Problem here in Mallorca is that to get anyone to come from Palma to look at the unit takes weeks.

The units with the problem are 021HWI and 036HWI, the problem is that the units appear to work correctly but after about 10-15 mins on cooling the unit turns itself off and the red defrost lamp flashes along with the green lamp. The unit will not then operate, but if it is disconnected from the power the unit resets itself and will wotrk again for 10 mins or so so turning itself off again. The problem has occured in three diferent units all at the same time? Any ideas????

Check you mains voltages: three units exhibit the same problem, unless they were installed with air in the system and are overheating because of (damaging) non-compressibles - some Q&C (quick and cheap) installers just "blow out" air (bad practice and illegal in the EU) Can you describe the units? Some SD units are far East standard rebages. From the Eurovent pages they ring familiar as low cost/efficiency R407 units with a small outdoor unit? What is the pattern of the flashes? PS tried to get some sense from the SD page... No comment, their scripts do not seem digestible on my PC.