Backpressure ValvesSeries FR • Temp. range: 40° to 450°FFully automatic valves maintain preset inlet pressure, regardless of variations. All have a stainless steel spring. Ranges are factory-set at midrange and can be adjusted in the field to meet specific application requirements. FNPT connections. Provide continuous protection of pumps, process piping systems, and similar equipment in most hydraulic systems.Meet CSA and CRN standards.