SUN HYDRAULICS
RSFCOBN

***Disclaimer: The following summary contains information gathered from various sources such as product descriptions, technical specifications and catalogs. While efforts have been made to provide accurate details, inaccuracies may occur. It is advised to verify all information by contacting Sun Hydraulics directly.***
The Sun Hydraulics RSFCOBN (RSFCOBN) is a pilot-operated, balanced piston sequence valve designed to supply a secondary circuit with flow once the pressure at the inlet port 1 exceeds the valve setting. This valve effectively controls the pressure at port 1 relative to the drain port 3 and remains unaffected by back pressure at port 2 up to the valve setting. It can be used in place of two-port relief valves for pressure regulation if there is existing pressure in the return line. The RSFCOBN model features interchangeable three-port sequence cartridges, ensuring identical flow paths and cavity compatibility for a given frame size. The pilot flow increases as inlet pressure rises above the set point relative to drain pressure. A stainless steel screen protects its main stage orifice, and it can handle pressures up to 5000 psi (350 bar) at port 3, with direct additive effects on the valve setting at a 1:1 ratio. However, it is not suitable for load holding applications due to spool leakage. The valve incorporates Sun's floating style construction to minimize binding risks from installation torque or machining variations. It supports EPDM seals for systems using phosphate ester fluids, but these seals are vulnerable to petroleum-based substances. The RSFCOBN has a capacity of 30 gpm (120 L/min) and operates with factory pressure settings established at 4 gpm (15 L/min). Its maximum operating pressure is 5000 psi (350 bar), with control pilot flow between 10-15 in\u00b3/min (0.16-0.25 L/min) and typical response time of approximately 10 ms. The maximum leakage rate is 3 in\u00b3/min (50 cc/min) at 1000 psi (70 bar). Adjustment requires up to five clockwise turns, with specific hex sizes needed for installation torque and adjustments: valve hex size is 1-1/8 in., internal hex size for adjustment screw is 5/32 in., locknut hex size is 9/16 in., and locknut torque measures between 80-90 lbf-in. The model weighs approximately .50 lb (.25 kg), and Viton seal kits are available under part number: 990202006.