We had a Mira Zest electric shower installed about two years ago. Over the last month in or so, it has started to make a loud clunking noise when being turned on and off.
The noise is louder on switch off, particularly if the flow rate has been set high. We don't have any issues with water hammer with any other taps/appliances which use the direct mains feed. We also haven't noticed any sharp increase in mains pressure.
Any help/advice would be greatly appreciated.