Last week we started to get a vibration on the cold pipes, making a very loud noise. I turned the cold water pressure down slightly at the stop tap and that seemed to cure that problem but since then we have very very low pressure on the hot water, ive turned the cold water pressure back up at the stop tap, this time we aren't getting the vibration but we still have no pressure on the hot water. Though when you first turn the hot water tap on it flows quite strongly for a few seconds then becomes a trickle. Also my wife thinks that in order for the water to be hot the heating needs to be switched on