Had my first minor flood happen yesterday from the ATO....................was definitely user error and not a problem with the ATO though. I turned the power off to the ATO then moved the water bin out of the way to adjust a circ pump then put it back when I was done and turned it back on. About 5 I took the cat out for his walk (yes I do!) just as the pump started to top up the tank, about 10 minutes later it is still going when I come back in but thought nothing of it, a few minutes later it was still on and I knew this just wasnt right. I had pulled out the feed line from the sump when I moved the bin and never even thought of it so it was pumping out all the RO into the base of the stand and onto the carpet..............about 5 litres worth so it could have been a lot worse!