Water is coming through the shower even the power is sour? I have a Neptune Solo 8.5 KW shower. this is the one:...

I have a Neptune Solo 8.5 KW shower. this is the one: http://www.mx-group.com/products.php?pa_...

To switch on the shower, here is an external switch. As soon as I switch on the shower the water starts flowing. The control knob on the shower system doesnt makes any difference. However, the hose down will heat up simply if I move the top knob as I was doing until that time (ie, the place where it should be). so the problem is I can not switch past its sell-by date the shower by turning the knob to to the stop position. Any idea what it should be and how i can resolve it. please serve.
Transfer Images to Shoe?
Answers:    This thing have to have some sort of electric silinoid to cut stale the water. It is any faulty or have some scale built up on it and isn't places properly.The website u listed doesnt present you much info, but if you can get it cleaned out I mull over you would benefit from an inline water filter to remove strong minerals from your water.