Hi - Please could someone offer some advice. Yesterday after I had a hot shower one of the copper pipes in the airing cupboard began vibrating loudly next to the emersion heater. The pipe runs up to the loft water tank. The noise was so loud I actually thought it was next door drilling (I live in a flat), but it was too early. Again the same happened later in the day and again this morning. Approx 5mins after having the hot water on one of the pipes makes a very loud humming noise? I await your replies - many thanks.