I have a 3 year old Mira Sport 8.5 Kw electric shower. After the water
starts flowing and I turn the control knob back to the off setting the water
continues to flow (cold) for up to half an hour. even with the isolator
tuned off.

I opened it up and found that if I tapped the first black camber after the
water inlet a pair of white levers slowly moved on the side and the water
was shut off. Seems some mechanical valve is sticking. Is it worth
dismantling the valve or just buying a new one? Is it serviceable? Has any
one taken one to pieces?

David