SUN HYDRAULICS
RELIEF CART
RPCCKNN

***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 RPCCKNN (RPCCKNN) is a pilot-operated, balanced-piston relief cartridge designed for pressure regulation in hydraulic systems. This normally closed valve begins to open when the inlet port pressure reaches the set value, allowing flow to the tank port and effectively regulating system pressure. Known for its accuracy and low-pressure rise versus flow, the RPCCKNN operates smoothly and quietly with moderate speed. It is compatible with cross-port relief circuits, accepting maximum pressure at port 2, but should be used with caution due to potential spool leakage. The valve's minimum setting is 75 psi (5 bar) across all spring ranges, and it is not recommended for load-holding applications due to this leakage potential. The RPCCKNN features a main stage orifice protected against contamination and utilizes Sun's floating style construction to prevent internal part binding from excessive installation torque or machining variations. It accommodates a maximum operating pressure of 5000 psi (350 bar) and has a typical response time of 10 milliseconds. The cartridge supports EPDM seals for use in systems with phosphate ester fluids; however, exposure to petroleum-based fluids can damage these seals. Additional specifications include a capacity of 12 gpm (45 L/min), factory pressure settings established at 4 gpm (15 L/min), and a maximum valve leakage of 2 in\u00b3/min at 110 SUS (24 cSt). The valve hex size measures 3/4 inch (19.1 mm), requiring an installation torque between 20-25 lbf ft (27-33 Nm). Adjustment is achieved through an internal hex screw sized at 5/32 inch (4 mm), while the locknut requires a torque of 80-90 lbf in (9-10 Nm). This model weighs approximately .20 lb (.10 kg) and comes with a Viton seal kit option under part number 990162006.