Siemens 171A-10301 2W 1/2", 0.63CV BALL VALVE ASSY, CHROME-PLAT BRASS BALL & BRASS STEM, FLOAT NSRSiemens 171A 10301 This 599 Series 2 way ball valve with a floating control fail in place actuator assembly, providing 200 psi close off, is used to control hot or chilled water and up to 50% Glycol solution in convectors, fan coil units, unit conditioners, radiation and reheat coils. This 1 2 inch valve is 0. 63 Cv, equal percentage flow characteristic, with chrome plated brass ball and brass stem, and an operating handle that can manually operate