SUN HYDRAULICS
RPKCKAN

***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 RPKCKAN (RPKCKAN) is a pilot-operated, balanced-piston relief cartridge designed for precise pressure regulation in hydraulic systems. This normally closed valve opens to tank port 2 when the inlet port 1 pressure reaches a predetermined setting, allowing flow to throttle and maintain consistent pressure. It features low pressure rise versus flow, smooth and quiet operation, and moderate response speed. The valve is capable of handling maximum pressure at port 2, making it suitable for cross-port relief circuits; however, users should consider spool leakage in such applications. A 150-micron stainless steel screen protects the main stage orifice. While not suitable for load-holding applications due to spool leakage, the valve's back pressure on tank port 2 adds directly to the valve setting at a 1:1 ratio. The RPKCKAN is interchangeable with other two-port relief cartridges of the same frame size, sharing identical flow paths and cavities. Cartridges configured with EPDM seals are compatible with phosphate ester fluids but can be damaged by petroleum-based substances. Corrosion-resistant options are available, denoted by model code suffixes AP or LH for external stainless steel or zinc-nickel components respectively. Sun's floating style construction minimizes internal part binding from installation torque or machining variations. The unit fits cavity T-18A, Series 4 and supports capacities up to 200 gpm (760 L/min) with a maximum operating pressure of 5000 psi (350 bar). It has a typical response time of 10 ms and allows maximum valve leakage of 5 in\u00b3/min (80 cc/min) at specified conditions. The adjustment range spans five clockwise turns to increase settings, using an internal hex adjustment screw sized at 5/32 inch (4 mm). The locknut requires a torque range of 80-90 lbf\u00b7in (9-10 Nm), while installation torque is between 350-375 lbf\u00b7ft (474-508 Nm). The model weighs approximately 2.50 lb (1.15 kg) and utilizes Viton seal kits like part number 990018006.