Seawater Pressure Relief Valve Model 750-20, UL/ULC Listed, FM Approved. This valve is a hydraulically operated pilot actuated automatic control valve designed specifically to automatically relieve excess pressure in fire protection pumping systems. Pilot controlled, it maintains constant system pressure at the pump discharge within very close limits as demands change. The main valve consists of a stainless steel body and only one moving part, an elastomeric liner or control element. The valve will control from no flow to full open flow without any chattering or slamming under low flow conditions. There is no slip-type friction because the valve has no bearings. The valve has an excellent resistance to cavitation with a Cf factor of 0.9. The valves can be supplied as a combination control valve with check. Pilot controls are fully piped at the factory and the valve is shipped complete, ready for installation. BASIC COMPONENTS: 100-42 Roll Seal main valve, CRL Pressure relief control, X44A Strainer & orifice assy, 81-01 Check valve. MATERRIAL SPESIFICATIONS: Body: 316L stainless steel, Liner: Natural rubber 65 durometer, Liner retainer: 18-8 stainless steel PILOT: Body: ASTM B61 Naval Bronze, Spring cover: ASTM B61 Bronze, Wetted parts: Bronze/Monel - Buna N ACCESSORIES: Chech Control: ASTM B61, Control piping: SS-316, Control fittings: SS-316 DESIGN DETAILS: End detail Wafer: Fits ANSI B16.5 class 125, 150, 250 & 300 flanges - End detail Flanged: ANSI B16.5 class 150 (fits class 125) OR ANSI B16.5 class 300 (fits class 250) - Maximum Relief Pressure: 400 psi - Maximum Differential: 150 psid continuous, 225 psid intermittent - Temperature range: 32-185 deg F - Flange Operating Pressure: Class 125-175 psi max., Class 150-275 psi max., Class 250-300 psi max., Class 300-720 psi max.