Bulletin 71.4:289 D 10 01 54 X0 1 2 August 1990 www.FISHERregulators.com 289 Series Spring-Loaded Relief Valves The 289 Series relief valve is a throttling relief valve used downstream of pressure regulators to protect the downstream system from overpressure. A smooth throttling action minimizes pressure surges in the system during emergency operation. These relief valves are available in 1/4, 3/4