Hi We have 2 of these installed in our B&B, we should have spent the extra and bought a Sanibest,, but they are double the price! The only problems we've encountered in 2 years have been blockages caused by sanitary products,(despite warnings in 8 languages)
As for automatic flushing the most likely cause is the cistern overflowing into the pan, this can be hard to see on shiny porcelain so dry a strip of the bowl above the waterline and see if any water runs into the pan,
The other cause maybe the small pressure switch under the left hand top panel, we replaced one with a similar part from RS components.
If its flushing OK normally, and your cistern is not overflowing. I personally wouldn't worry about it.
Hope this is of some help Willl33
Willl33
April 2009