Pressure Regulating Valves Pressure regulating valve - PRESO | ARI Pressure regulating valve - PRESO | ARI The ARI-PRESO® is a spring-loaded pressure regulating valve designed for automatic pressure control in pumping systems, bypass lines, and condensate management. The valve ensures a stable flow and protects equipment from pressure fluctuations. View Flanged PN 16 DIN EN-JL 1040 (GG25) Cast iron EN-JS 1049 1.0619+N 1.4408