Key Specifications & Parameters Parameter Specification Notes Model Series YD (Diaphragm Pilot), YS (Piston Pilot) Type Pilot-Operated, Pressure Reducing Regulator Primary Function Pressure Reducing Sizes 1/2 inch to 8 inches (DN 15 to DN 200) Larger sizes available for specific requirements. End Connections Flanged: ANSI Class 125, 150, 250, 300 (depending on body material) NPT: Available in smaller sizes. Pressure Ratings Body Ratings: ANSI Class 125, 150, 250, 300 Max. Inlet Pressure (P1): Up to 400 psig (27.6 bar) for certain sizes/materials. Outlet Pressure (P2) Ranges: Various pilot springs available, typically covering ranges from 5 to 300 psig (0.3 to 20.7 bar). The wide range is achieved by changing the pilot spring. Temperature Range YD (Diaphragm Pilot): Up to 406°F (208°C) YS (Piston Pilot): Up to 800°F (427°C) The YS is the clear choice for high-temperature superheated steam. Body Materials Standard: Ductile Iron (for steam service) Common Options: Cast Iron, Carbon Steel (WCB), Bronze. Material selection is critical for the application fluid. Trim Materials Stainless Steel, Stainless Steel with Stellite hard-facing (for erosive service). Flow Capacity (Cv) Very High. Significantly higher than same-size direct-operated regulators. Specific Cv depends on size and trim. (e.g., a 2" YD/YS can have a Cv over 100). This is a key advantage of the pilot-operated design. Pilot Options Various internal and external pilots available for specific control needs, including absolute pressure pilots (for vacuum breaker or back-pressure service) and temperature pilots. This versatility allows the YD/YS to be used for more than just pressure reduction. Accessories Internal Check Valve: Prevents reverse flow. Separate Strainer: Recommended to protect the pilot from debris.