SUN HYDRAULICS
RELIEF CART
RDDALDN

***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 RDDALDN (RDDALDN) is a direct-acting relief cartridge valve designed to protect hydraulic components from pressure transients. This valve is normally closed and operates by opening to the tank port when the inlet pressure reaches the valve setting, thereby throttling flow and limiting pressure rise. It is noted for being smooth, quiet, essentially zero leak, dirt tolerant, immune to silting, and very fast in response time. The RDDALDN 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. This valve can only be adjusted when system pressure is removed; adjustment involves checking the setting, removing pressure, adjusting the valve, and rechecking the setting. The RDDALDN is relatively insensitive to changes in oil temperature and contamination levels, ensuring reliability across various conditions. It is particularly suitable for load-holding applications due to its design features. The back pressure on tank port 2 directly adds to the valve setting at a 1:1 ratio. For systems using phosphate ester fluids, cartridges with EPDM seals are available; however, exposure to petroleum-based fluids will damage these seals. This model incorporates Sun's floating style construction to minimize internal part binding due to excessive installation torque or machining variations in cavities/cartridges. With a cavity size of T-10A Series 1 and a capacity of 25 gpm (95 L/min), it has a maximum operating pressure of 5000 psi (350 bar). The typical response time is approximately 2 ms with a maximum leakage rate at reseat of 10 drops/min (0.7 cc/min). Factory settings are established at 4 gpm (15 L/min), with reseat occurring at approximately 90% of the set value.