SUN HYDRAULICS
RBFALWN

***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 RBFALWN (RBFALWN) is a bidirectional, direct-acting relief cartridge valve designed to protect hydraulic components from pressure transients. This normally closed, pressure-limiting valve begins to open when the pressure differential between ports 1 and 2 exceeds the set threshold, effectively throttling flow to limit pressure rise in both directions. Notably, the internal modulating mechanism makes it resistant to cavitation-related issues such as noise and manifold erosion. The valve's adjust screw seals are exposed to pressure at port 1, requiring adjustment when the pressure is removed or via port 2. It operates reliably across varying oil temperatures and contamination levels. To ensure optimal repeatability, select a spring range where the desired relief setting is midrange to high within the specified limits. The RBFALWN features Sun's floating style construction, minimizing internal binding risks due to installation torque or machining variations. It fits within a T-3A cavity for series 2 applications with a capacity of up to 30 gpm (120 L/min) and operates at a maximum pressure of 5000 psi (350 bar). The typical response time is about 2 milliseconds with maximum valve leakage at reseat limited to 30 drops per minute, maintaining reseat at approximately 85% of the setting. Hysteresis measures around 3%, with adjustment facilitated by five clockwise turns for increased settings. The valve has a hex size of 1-1/8 inches (28.6 mm) and requires an installation torque of 45-50 lbf ft (61-68 Nm). A Viton seal kit is available under part number 990303006 for maintenance purposes.