R900962883 DR10-4-5X/100YM Rexroth pilot operated relief valve

FAQs for Rexroth DR10-4-5X/100YM Relief Valve

1. Q: How is a pilot-operated relief valve different from a direct-acting one?

   A:​ A pilot-operated relief valve (like this DR10) is a two-stage design. A small, direct-acting pilot stage​ senses system pressure and controls a larger main stage piston. This allows for very precise pressure control with minimal "override" (the difference between cracking pressure and full-flow pressure), especially at high flows. A direct-acting valve (like a DBDS) is a single-stage device where pressure acts directly on the poppet; it's simpler and faster but has more override at high flow.

2. Q: The valve is rated for 100 bar. What is the correct procedure to adjust it?

   A:​ The pressure is adjusted via the pilot stage screw​ (usually a smaller, separate screw from the main cartridge body). To increase pressure, turn the screw clockwise; to decrease, turn counter-clockwise. Crucially, adjustments should be made while the system is under flow, and the pressure should be monitored with a gauge. After setting, the lock nut must be securely tightened​ to prevent drift. Never adjust beyond the 100 bar maximum.

3. Q: Where is the "pilot stage" located, and does it require a separate connection?

   A:​ The pilot stage is integrated into the cartridge valve itself. It is typically a small, machined section within the valve body that uses internal drilling to sense pressure from the main inlet (P). It does not​ require an external pilot pressure supply. However, the pilot stage has a very small drain orifice that must be connected internally or externally to the tank (T) with zero backpressure​ for proper function.

4. Q: The valve is leaking internally to the tank even when pressure is below the set point. What's wrong?

   A:​ For a pilot-operated valve, this usually indicates a problem with the pilot stage or the main piston. Causes include: 1) Contamination:​ A tiny piece of dirt on the pilot poppet seat or the main piston lands is the most common cause. 2) Worn Components:​ Wear on the pilot poppet or the main piston/cylinder bore. 3) Damaged Seal:​ A failed seal on the main piston. The valve should be disassembled, cleaned thoroughly, and inspected. Often, simply flushing the valve can resolve the issue.

5. Q: This valve has a 10mm nominal size. How do I determine if it's the right size for my system's flow?

   A:​ The 10mm size refers to the mounting cavity (ISO 7368 Size 10). Its flow capacity depends on the pressure setting. You must consult the valve's official pressure-flow characteristic curve​ in the datasheet. Find your required maximum system flow​ on the curve and ensure it intersects at a pressure below​ your desired set pressure. If your flow requirement is at the far right of the curve, the valve is undersized and will cause excessive pressure override and heat.