The diverter valve is an essential part within the shower as it allows the user to divert the flow of the water to the fixture of their choice e.g. the shower head. Many homes choose a dual bath/shower, this is where the diverter valve is needed, it can normally be found between the tap and shower arm. The external part of the valve (knob or lever) is used to direct the water towards either the tap or the shower head by opening or closing the tap opening. When the lever opens the tap line, this reduces the pressure and means that the water doesn’t have the pressure to travel up the shower arm, so will instead go through the tap. If the tap line is closed, then pressure builds and the water is able to go up to the shower arm.
Depending on the needs of the particular shower the diverter valve will be either 2 way or 3 way.