PA PULSAR RV Pressure Regulating Unloader Valves. At gun closure, the waterflow is discharged in bypass reducing the pressure in the system upstream of the valve. Optimized internal passages that guarantee reduced pressure loss. Antirotation device of the piston positioned inside the valve and obtained by an hexagonal sector of the piston itself. O-rings of the fittings positioned upstream to the thread : no risk of fittings ejected in case of overpressure. Double feed connection. Version with knob fitted with locknut for minimum working pressure adjustment.