How can I fix my redring selectronic shower?

When I turn on the shower isolating switch the water automatically runs from the shower without it turned on. When the shower is turned on it is in temp lock, this can be overridden and shower will work. Only way to stop water coming from the shower is to turn of the isolating switch. Please help, solenoid and valve have been changed as told by redring but still the same. All help greatly appreciated????