R901275714 DREE20-6X/200YMG24K31A1M Hydraulic proportional relief valve from Rexroth, Germany

FAQ:

1. Integrated Electronics (OBE)

   The "E"​ in DREE​ confirms On-Board Electronics (OBE). This means the valve contains its own amplifier. You supply 24V DC power​ and a 0–10 V command signal​ directly to the valve's K31 connector. This simplifies wiring and eliminates the need for an external VT-VSPA amplifier.

2. Mechanical Maximum Pressure Limiter (M)

   The "M"​ immediately after DREE20​ indicates the valve includes a mechanical safety relief valve​ as a maximum pressure limiter. This is a safety feature that hydraulically limits the maximum pressure at port A to approximately 350 bar, protecting the system in case of an electrical control fault.

3. Pressure Rating & Flow (200 bar / 300 L/min)

   The "200"​ denotes the maximum electrically adjustable reduced pressure​ at port A. This is a high-flow variant​ (max flow 300 L/min), suitable for large actuator circuits or secondary pressure control in high-power systems.

4. External Pilot Drain (Y) & No Check Valve

   • "Y": The pilot control oil must be drained externally via port Y. This port must be connected directly to the tank with minimal backpressure. High backpressure at Y will cause inaccurate pressure regulation.

   • "M" at the end: The suffix "M" indicates no check valve​ is included between ports A and B. This means flow from port A back to port B is blocked by the spool design. If your application requires free reverse flow (A→B), you would need a variant without the final "M" code.

5. Critical Installation Notes

   • Port Y Drain:​ Must be piped separately to tank​ with a line diameter ≥ 5 mm and length < 2.5 m to avoid backpressure issues.

   • Zero Signal Pressure:​ With a 0 V command signal, the valve maintains a minimum pressure of approximately 2 bar​ at port A.

   • Subplate:​ Requires an NG20 subplate according to ISO 5781-AG-10-2-A (e.g., Rexroth RE 45102 series).

Correction:​ Your description mentioned "proportional relief valve", but this model is specifically a proportional pressure reducing valve. It controls the downstream (A-port) pressure, not the system relief pressure.