SUN HYDRAULICS
RELIEF CART
RDDALDV

***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 RDDALDV (RDDALDV) is a direct-acting relief cartridge designed to protect hydraulic components from pressure transients by limiting pressure rise through throttling flow to the tank port when the inlet pressure reaches the valve setting. This normally closed, pressure-limiting valve is characterized by its smooth and quiet operation, essentially zero leakage, dirt tolerance, and rapid response time. It features a two-port design and is physically and functionally interchangeable with other relief cartridges of the same frame size. The valve can handle a maximum operating pressure of 5000 psi (350 bar) and has a capacity of 25 gpm (95 L/min). The RDDALDV is suitable for cross-port relief circuits and load-holding applications due to its ability to accept maximum pressure at port 2. The valve's design incorporates Sun's floating style construction, minimizing internal part binding risks from excessive installation torque or machining variations. It is relatively insensitive to changes in oil temperature and contamination, ensuring consistent performance. To adjust the valve setting, system pressure must be removed as the seals on the adjustment screw are exposed to system pressure. Selecting a spring range where the desired relief setting falls between midrange and high ensures maximum repeatability. Back pressure on port 2 directly adds to the valve setting at a 1:1 ratio. The RDDALDV can be configured with EPDM seals for use in systems utilizing phosphate ester fluids; however, exposure to petroleum-based fluids should be avoided as it will damage these seals. The cartridge's compact dimensions include a valve hex size of 7/8 inch (22.2 mm) and an installation torque requirement of 30-35 lbf ft (41-47 Nm).