Turn on the shower and go watch the pressure guage on the pump. When the pressure goes from 50 to 30 the pump will come on. If while the shower is still running the pressure goes back up to 50 and shuts off the pump, a CSV will solve that proplem and give you much better pressure. If the pressure just stays low while the shower is on, you are running low on water or pump size. You also need to let a little air out of the tank. Should be no more air than 28 PSI.