R900424277 DBDS20P1X/200 Direct acting relief valve made by Rexroth in Germany

FAQs for Rexroth DBDS20P1X/200 Direct-Acting Relief Valve

Q: This valve is rated for 200 bar. How do I adjust it to a lower pressure, like 50 bar?

A:​ The valve has a wide adjustment range, from approximately 5 bar up to its maximum of 200 bar. You adjust it by turning the external screw. To lower the pressure setting, turn the screw counter-clockwise. It is crucial to adjust the pressure while the system is under flow conditions, monitor the pressure with a gauge, and then securely tighten the lock nut to prevent the setting from changing due to vibration.

• Q: What is the main application for a direct-acting relief valve versus a pilot-operated one?

  A:​ A direct-acting relief valve, like the DBDS, is typically used for pressure limitation in systems with moderate to high flows where some pressure override (the difference between cracking pressure and full flow pressure) is acceptable. It reacts quickly and is robust. A pilot-operated valve is preferred for very high flows or where minimal pressure override and precise pressure control are critical, as it offers better stability and efficiency at high flow rates.

• Q: The valve ports are marked P and T. How should they be connected?

  A:​ Port P​ is the pressure inlet and should be connected to the system pressure line you wish to limit. Port T​ is the tank outlet and must be connected directly to the reservoir (tank) with a low-pressure, unrestricted line. Connecting these ports incorrectly will render the valve inoperative and may be unsafe.

• Q: The valve is leaking to the tank even when system pressure is low. What could be the cause?

  A:​ Continuous leakage below the set pressure is most commonly caused by contamination. A tiny particle of dirt trapped on the valve seat or spool can prevent it from sealing completely. Other causes include a damaged seal, a worn or scored spool/seat from cavitation, or the pressure setting being accidentally lower than intended. Start by checking and cleaning the valve cartridge.

• Q: What does the "20" in DBDS20P1X signify, and how does it differ from a DBDS10 model?

  A:​ The number (10, 20, 30, etc.) indicates the nominal size​ of the valve, which relates to its flow capacity and physical port dimensions. A DBDS20​ has larger internal orifices and ports (7/8" - 14 UNF) than a DBDS10, allowing it to handle higher flow rates (up to ~120 L/min vs. ~60 L/min for a DBDS10) at a given pressure drop. Select the size based on your system's required flow.