Occasionally when using the electric shower, I get a very very loud vibration (sounds like someone is drilling through the wall), which stops shortly after turning the shower off.
This has also happened a couple of times when we've not been using the water (no toilet cistern filling, washing machine and dishwasher off etc). This lasts a few minutes and is pretty scary. Vibration seems strongest on cold water pipes. The last time it happened, we rushed around the house trying to find the source - the noise was loudest in the upstrairs hall - coming from the loft above the hot water cylinder. When it has happened I've turned on a few taps in case it helps, but doesn't have an immediate obvious effect. I've found various posts on noise/vibration/humming, but this is VERY loud, you can feel the vibration in the walls, cielings, floor and door frames!!! oh, and the pump for the hot water in the airing cupboard was not pumping (but there may be a second pump with the backboiler, but I can't really access it).
Any ideas on the causes - I'm going to try and clear any potential air locks using http://www.diydoctor.org.uk/projects/curingairlock.htm tonight in case that is the problem, but I'm unsure.
Some posts have suggested the storage tank ball cock - can a fault in this really be so noisey - there is a lot of power in whatever the cause is?
Any help really appreciated - the house has been 'improved' by many a bodge DIYing boyfriends of the previous owner and has many accentricities (like we've had to have a number of sockets and the living room lights condemned after we were getting shocks! and many more).
Any help appreciated,