My exact circumstances were that the unit ran error free since I installed it (about 1 year). During this time, we had loadshedding. A few days before christmas, our grid supply was back to full on 24/7. It was during this time of continuos supply that the error popped up.
There wasn't a power...
I have had the unit for just over a year - it has ran flawlessly in that time. The error only appeared about 4 days ago and similar to other contributors, after a period of continuous power supply from the grid.