SUN HYDRAULICS
RSFCQDN

***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 RSFCQDN (RSFCQDN) is a pilot-operated, balanced piston sequence valve designed to supply a secondary circuit with flow once the pressure at inlet port 1 exceeds the valve setting. This valve manages pressure at port 1 relative to the pressure at drain port 3 and is insensitive to back pressure at port 2 up to the valve setting. Notably, it can regulate pressure in place of two-port relief valves if there is pressure in the return line. The RSFCQDN model features a main stage orifice protected by a 150-micron stainless steel screen and accommodates a maximum operating pressure of 5000 psi (350 bar). It is not suitable for load-holding applications due to spool leakage. The valve's design includes Sun's floating style construction, minimizing internal part binding risks due to excessive installation torque or machining variations. This sequence valve offers flexibility with W and Y control options, adjustable throughout their full range unless a special setting is specified, which defines the maximum setting. Cartridges with EPDM seals are intended for systems using phosphate ester fluids and should avoid exposure to petroleum-based fluids. With a capacity of 30 gpm (120 L/min) and factory pressure settings established at 4 gpm (15 L/min), the RSFCQDN ensures efficient performance across various applications. The response time is typically around 10 ms, with maximum valve leakage measured at three cubic inches per minute at 1000 psi (50 cc/min at 70 bar). Installation requires specific torque settings: valve hex size of 1-1/8 inches (28.6 mm), installation torque between 45-50 lbf-ft (61-68 Nm), adjustment screw internal hex size of 5/32 inches (4 mm), locknut hex size of 9/16 inches (15 mm), and locknut torque between 80-90 lbf-in (9-10 Nm). The model weighs approximately .50 lb (.25 kg) and utilizes Viton seal kits for durability and performance consistency.