The majority of the pressurized irrigation systems will require a pressure regulator except for gravity-based irrigation systems working at either low pressure or low flow rate. While designing an irrigation system Pressure regulator, it should be kept in mind that there must be sufficient flow in the system as well as a pressure difference of 0.3 to 1 bar between the inlet and regulating pressure.

Water flows through the inlet, around the seat, and through the t-stem. Water pressure acting on the diaphragm forces the spring to compress, pushing the t-stem toward the seat. The closing of the area between the seat and the t-stem reduces the water pressure on the diaphragm. The balance between the force on the diaphragm and spring resistance establishes the outlet pressure.

Irrigation pressure regulators need outflow and back pressure to regulate the pressure within your irrigation system. With no water flowing through the regulator, the inlet and outlet pressures will measure the same. To verify the pressure maintained in your system, one will need to place a pressure gauge at the end of one of the zones, turn the zone on, let it pressurize and once the lines have filled and emitters begin to flow then take the reading. This will reflect the working pressure within your system.

Because of this, a certain amount of pressure (bar) and flow (m3/h) is required for a pressure regulator to operate.