The 2 tanks are full and there is water going through every pipe in the house, there is just no hot water going to the taps in upstairs bathroom, them 2 tanks were empty yesterday and are full today, I have pressed the reset button on the cylinder and it's on the + symbol also, when I try to fire up the boiler it's starting for a few seconds and as soon as its try's to fire up it's making a strange sound and not firing at all now, have you any ideas, I will get a plumber in if I can't resolve this thanks .