R900410880 ZDR10DP2-5X/150YM Rexroth overflow valve direct acting hydraulic valve

FAQs for Rexroth ZDR10DP2-5X/150YM Pressure Reducing Valve

• Q: This 10mm valve is rated for 150 bar secondary pressure. How do I choose between this and a 6mm model with the same 150 bar rating?

  A:​ The choice is based on required flow. The 10mm valve (ZDR10DP2) can handle approximately 60 L/min, while a 6mm valve (ZDR6DP2) handles about 20 L/min​ at the same pressure drop. If your secondary circuit's flow demand is high (e.g., supplying a large cylinder or motor), choose the 10mm valve. For lower flow circuits, the 6mm valve is smaller, more economical, and sufficient. Using an undersized valve causes excessive pressure drop and heat.

• Q: How does the "P2" performance characteristic differ from other variants like "A2" or "B2"?

  A:​ The "P2" is a specific performance curve code​ designated by Rexroth. It defines the precise relationship between the spool's position, the flow through the valve, and the resulting regulated pressure. This affects characteristics like linearity, minimum controllable pressure, and stability. The "P2" variant is tuned for a particular set of applications. For critical control, you must consult the official valve datasheet to ensure the "P2" curve meets your system's dynamic response requirements.

• Q: The system is generating a lot of heat, and we traced it to this valve. Why?

  A:​ Direct-acting reducing valves are inherently inefficient​ when actively regulating. They generate heat in two ways: 1) Throttling Loss:​ Energy is dissipated as heat when reducing high inlet pressure (P) to a lower outlet pressure (A). 2) Internal Bypass Loss:​ The constant leakage flow from P to T (a normal function) carries unused pump energy straight to the tank as heat. The higher the pressure drop and the higher the bypass flow, the greater the heat generation. For continuous, high-power pressure reduction, consider more efficient alternatives like a pressure-compensated pump.

Q: Can I use this valve to create two different, stable pressure levels in one system?

A:​ Yes, absolutely. This is a classic application. You would install one reducing valve in a branch circuit to create the lower, secondary pressure (e.g., 80 bar for a clamp), while the main system relief valve sets the higher primary pressure (e.g., 210 bar for the main cylinder). The reducing valve isolates the secondary circuit, maintaining its 80 bar regardless of the 210 bar main system pressure.

Q: The downstream pressure slowly drops to zero when the actuator is holding position. Is the valve faulty?

A:​ Not necessarily. This is a fundamental trait of a direct-acting reducing valve supplying a sealed, static volume. The valve's internal leakage (P to T) provides the only path for makeup flow. If the downstream circuit is perfectly sealed, this leakage will eventually cause pressure decay. The valve is working, but its design includes this leakage. For long-term, zero-leakage pressure holding (e.g., a safety clamp), the circuit should include an accumulator​ on the secondary side or use a pilot-operated reducing valve​ with much lower leakage.