Electric shower problem.

[astroarcadia]

We have downstairs a Mira electric shower that has started to make a knocking noise when in use. It sounds like the noise is coming from inside the unit and knocks about once a second. Nothing has changed elsewhere in the house that might alter the pressure.

Anybody have any ideas what could be wrong?

TIA

[TheD]

Thats what they call a water hammer. I'm not to hot on the actual correct solution but with me it was a pressure and air problem.

[netherfield]

looked on here for a solution.

http://www.mirashowers.co.uk/home.htm