SUN HYDRAULICS
RDJALBN

***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 RDJALBN (Material Number: RDJALBN) is a direct-acting relief cartridge designed to protect hydraulic components from pressure transients. These normally closed, pressure-limiting valves open to the tank port when the inlet port pressure reaches the valve setting, effectively throttling flow to limit pressure rise. Characterized by smooth and quiet operation, these valves are essentially zero-leak, dirt-tolerant, immune to silting, and exhibit rapid response times. The RDJALBN model is interchangeable with other 2-port relief cartridges of the same frame size and flow path. It accepts maximum pressure at port 2 and is suitable for cross-port relief circuits and load-holding applications. With a cavity size of T-18A and a series 4 capacity of 200 gpm (760 L/min), this valve operates at pressures up to 5000 psi (350 bar) with a typical response time of 2 ms. The adjustment procedure involves removing system pressure before making any changes due to seal exposure on the adjust screw. For optimal performance, select a spring range where the desired relief setting falls between midrange and high within its limits. Notably, back pressure on tank port 2 directly adds to the valve setting at a 1:1 ratio. Cartridges with EPDM seals are intended for systems using phosphate ester fluids; exposure to petroleum-based fluids can damage these seals. The Sun floating style construction minimizes internal part binding risks due to excessive installation torque or machining variations in cavity/cartridge interfaces. Additional specifications include a maximum valve leakage at reseat of 10 drops/min (0.7 cc/min), reseat at 90% of setting, adjustment range via five clockwise turns for increased settings, valve hex size of 1-5/8 inches (41.3 mm), installation torque between 350-375 lbf ft (474-508 Nm), adjustment screw internal hex size of 5/32 inches (4 mm), locknut hex size of 9/16 inches (15 mm), locknut torque between 80-90 lbf in (9-10 Nm), model weight of approximately 3.30 lb (1.50 kg), and Viton seal kit availability under part number 990318006.