This Pressure Regulator is designed for single or multiple pump, weep or multi-nozzle systems. This design easily plumbed into the discharge line or directly onto the discharge head using a tee fitting. This regulator maintains set system pressure even when only one of several guns or nozzles is performing or a solenoid valve is open, by-passing the unused flow. The pressure is held in the line during full by-pass and instantly has full pressure, when all guns and nozzle resume operation. 5-10% by-pass is necessary for optimum performance.