R900450964 DR6DP2-5X/75YM Direct acting pressure reducing valve from Rexroth, Germany

FAQs for Rexroth DR6DP2-5X/75YM Pressure Reducing Valve

1. Q: This valve is rated for 75 bar secondary pressure. How is that different from the 25YM model?

   A:​ The key difference is the maximum adjustable secondary pressure. The DR6DP2-5X/75YM​ can be set up to 75 bar, while the DR6DP1-5X/25YM​ is limited to 25 bar. The internal spring in the 75YM model is calibrated for this higher force range, allowing it to regulate a higher downstream pressure. The nominal size, flow capacity, and function are otherwise the same. Select the valve that matches your required secondary circuit pressure.

2. Q: How do I set the desired pressure on this valve?

   A:​ The pressure is set mechanically​ using the external adjustment screw. To increase the pressure at the A (outlet) port, turn the screw clockwise. To decrease it, turn the screw counter-clockwise. Always make adjustments while the downstream circuit is under flow, monitor the pressure with a gauge, and finally tighten the lock nut to secure the setting against vibration.

3. Q: I need the secondary pressure to be very stable. What factors can cause it to fluctuate?

   A:​ Pressure instability can be caused by: 1) Large variations in primary (inlet) pressure​ that exceed the valve's regulation capacity. 2) Rapid changes in flow demand​ from the secondary circuit. 3) Contamination​ causing the spool to stick intermittently. 4) Excessive backpressure in the T (tank) line.​ For the most stable regulation, ensure a relatively steady inlet pressure, a reasonably constant flow demand, clean oil, and a direct, low-pressure tank connection for the T port.

4. Q: The valve has a continuous, small flow to the tank (T port). Is this a leak, and is it necessary?

   A:​ This is not a defect; it is a functional characteristic​ of a standard direct-acting reducing valve. This small internal leakage (from P to T) occurs when the valve is in the regulating state but the secondary circuit demand is low. It allows the valve to respond instantly to a sudden demand for flow. While it ensures good response, it also represents a constant energy loss (heat generation). For circuits that hold pressure for long periods without needing flow, a "zero-leakage" or pilot-operated reducing valve might be a more efficient choice.

5. Q: Can I use this valve to control the pressure on both sides of a double-acting cylinder?

   A: No, not with a single valve.​ A standard 3-port reducing valve (P, A, T) supplies and regulates pressure to one line. To independently control the pressure on both sides of a cylinder (e.g., for force control), you would need two separate reducing valves—one for the cap side (A port) and one for the rod side (B port) of the cylinder, each connected to the pressure source.