SUN HYDRAULICS CORP
RDDTQCV
Pressure Control

Direct-acting relief cartridges are normally closed, pressure-limiting valves used to protect hydraulic components from pressure transients. When the pressure at the inlet (port 1) reaches the valve setting, the valve starts to open to tank (port 2), throttling flow to limit the pressure rise. These valves are smooth and quiet, essentially zero leak, dirt tolerant, immune to silting and are very fast. The CE marked valve is a safety valve that meets the requirements of the European Directive for Pressurized Devices (PED) 97/23/EC. The valve setting represents the excess operating pressure at which the valve opens. Valve capacity can be determined from the performance curve. It shows an approved flow which depends on the excess operating pressure. As a requirement of the PED, the system pressure at the maximum approved flow is a maximum of 10% above the excess operating pressure.

• Standard settings for preset valves include:
  • A adjustment range: 100 bar, 140 bar, 160 bar and 210 bar
  • W adjustment range: 250 bar
  • C adjustment range: 330 bar
  Other settings are available upon request.
• At this time RDDT and RDFT are the only Sun relief valves that are CE marked.
• Each delivery contains a TÜV-Approval, which is a certification of the excess operating pressure and the approved flow, an EC Declaration of conformity and an instructional manual.
• Pressure settings from 90 bar up to 422 bar are approved and certified by TÜV
• Will accept maximum pressure at port 2; suitable for use in cross port relief circuits.
• Valve is relatively insensitive to varying oil temperatures and oil borne contamination.
• Suitable for use in load holding applications.
• Back pressure on the tank port (port 2) is directly additive to the valve setting at a 1:1 ratio.
• Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge machining variations.

Additional Resources

• Sun Offers Zinc-Nickel Plating for Corrosion Resistance
• Sun Cartridges with EPDM Seals
• Series 4 PLUS Cartridges Offer Higher Flows with Lower Pressure Losses
• Pilot-Operated, Balanced Poppet, Anti Shock Reliefs
• CavitySaver multi-function valves deliver single-cartridge solutions
• 'Soft' Relief Eliminates Pressure Spikes
• Tri-Grip Handknob Now Offered From Sun as a Standard Control Option
• QuickDesign with SmartConnect Offers Drag-and-Drop Schematic Tool
• Sun Introduces 'Hybrid' Valves
• CE/TÜV Certified Pressure Relief Valves
• Pressure Relief and Regulating Cartridge Valve Technical Tips
• Pilot Operated, Balanced Poppet Relief Valves
• Sun Expands Corrosion-Resistant Solutions
• Pressure Relief and Regulating Valves
• Manufacturing Sun Cartridge Cavities
• Performance Data
• Sun's Floating Style Screw-In Cartridge
• Units of Measure, Settings, and Conversions
• Cavity Information (S-171) and Tooling
• Sun Model Code Explanation; 999-901-334
• Cartridges: Materials of Construction
• Fluid and Temperature Recommendations