Siemens 171H-10305 2W 1/2", 4CV BALL VALVE ASSY, CHROME-PLAT BRASS BALL & BRASS STEM, 2-POS NO SRSiemens 171H 10305 This 599 Series 2 way ball valve with a 2 position control, normally open, fail safe 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 4. 0 Cv, equal percentage flow characteristic, with chrome plated brass ball and brass stem, and an operating handle that can