Kunkle 71S

Cast iron non-code liquid relief valve with a stainless steel seat and disc and a pressure-tight hood. The cast iron body makes the 71S the economical choice where the service allows it, at the cost of range: 1 to 250 psig and −20°F to 406°F, against 400 psig and 550°F on the carbon steel and stainless models. FNPT 1/2″ through 2″, relieving 1 to 296 GPM at 25% accumulation. Trim is stainless throughout — A479-316 nozzle (A351-CF8M at 1-1/2″ and 2″), A743-CF8M disc, A313-316 spring. Non-code: no ASME stamp, no National Board certification. Maximum back pressure 50 psig. If you need a higher ceiling or a wider temperature range, specify the 171.