whats up with my tritont300si shower?

ive installed a triton t300si shower ,water pressure is ok,filter is clean,hoses are clear,but low pressure light is on.After start up period, once started start button flashes,water spurts and there is a clicking sound coming from the pcb,and 3 flashes. The switch at bottom of pcb/top of stabiliser valve assembly is switching constantly and low pressure light stays on.