Kunkle 71S/171/171P/171S

Kunkle 71S, 171, 171P and 171S are extra-heavy, rugged non-code liquid relief valves for overpressure relief, pressure regulation, by-pass relief and the protection of pumps, tanks, lines and hydraulic systems carrying acid, caustic, ammonia and other corrosive liquids. All four share the same design — lapped seats, a spherical pivot between disc and spring to correct misalignment, stainless steel springs — and differ only in body material and lever type. FNPT connections from 1/2″ through 2″, relieving 1 to 374 GPM at 25% accumulation depending on size. Choose by material and service temperature: 71S cast iron, to 250 psig and 406°F; 171 carbon steel, to 400 psig and 550°F; 171P the same as the 171 with a packed lift lever; 171S all 316 stainless including the spring. These valves carry no ASME stamp and no National Board certification — they are not code valves. Maximum back pressure is 50 psig, and back pressure increases set pressure on a one-to-one basis while reducing capacity.