We have some new fangled flushing system on our toilet that came with the house, basically it looks like some kind of vaccum set up where you push a button on the front of the cystern and air pressure operates some kind of diaphragm...sorry for the poor description, anyway just lately I've noticed a continual dripple into the pan...not much but it does seem to be increasing, I'm guessing somethings worn out but don't have a clue where to start diagnosing....does anyone know of this type of system and have any idea where the fault might lie?...thanks