Solenoid operated pilot relief assembly


Function for XRAG: Normally Open
Normally Open
Port Designators [ + ]
Modifiers Ports
A, A/S Ports 1 & 2: 1/4" NPTF; Port G: 1/4" NPTF;
I, I/S Ports 1 & 2: SAE 6; Port G: 1/4" NPTF;
T, T/S Ports 1 & 2: 1/4" BSPP; Port G: 1/4" BSPP;
Technical Features [ + ]

This assembly consists of a direct-acting relief cartridge which 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 2-way, 2-position solenoid directional valve provides a means to unload (bypass the relief valve) the system.

  • Back pressure on the tank port (port 2) is directly additive to the valve setting at a 1:1 ratio.
  • Suitable for use in load holding applications.
  • This assembly provides protection for pumps and motors from pressure transients due to sudden load changes, especially variable displacement pumps, since the displacement mechanism is sometimes too slow to catch these pressure transients.
  • The assembly's direct acting relief valves exhibit rapid response characteristics that minimize pressure overshoot and also provide low reseat leakage (less than 5 drops/min (0,3 cc/min) @ 85% of cracking pressure).
  • The seals on the adjust screw are exposed to system pressure which means this valve can only be adjusted when the pressure is removed. The setting procedure is; check the setting, remove the pressure, adjust the valve, check the new setting.
Technical Data [ + ]
Body Type Line mountLine mount
Capacity .25 gpm1 L/min.
Mounting Hole Diameter .34 in.8.6 mm
Mounting Hole Thread .250-20 UNC - 2B in..250-20 UNC - 2B in.
Mounting Hole Depth ThroughThrough
Mounting Hole Quantity 11
FAQs [ + ]

There are exactly 250 Sun drops in a cubic inch or 15 in a cc.

Direct-acting valves are used to prevent over pressure, and pilot-operated valves are used to regulate pressure. If you are unsure, use a direct-acting valve. Sun's direct acting valves are very fast, dirt tolerant, stable, and robust. Sun's pilot-operated valves are moderately fast, they have a low pressure rise vs. flow curve, and they are easy to adjust.

Notes [ + ]
  • Important: Carefully consider the maximum system pressure. The pressure rating of the manifold is dependent on the manifold material, with the port type/size a secondary consideration. Manifolds constructed of aluminum are not rated for pressures higher than 3000 psi (210 bar), regardless of the port type/size specified.
Additional Resources [ + ]
Coil Information [ + ]

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