Product Overview

The 4WREE6E16 and 4WREE10E25 are Bosch Rexroth direct-operated proportional directional valves with electrical spool-position feedback and integrated valve electronics (OBE).

Rexroth defines the 4WREE as a proportional directional valve designed for controlling both the direction and magnitude of hydraulic flow. The valve uses proportional solenoids for direct spool actuation, electrical position feedback for spool monitoring and integrated electronics for signal processing.

The verified configurations are:

4WREE 10 E25-2X/G24K31/A1V
Material Number: R900933073

and:

4WREE 6 E16-2X/G24K31/A1V-655
Material Number: R900950342.

The second model is important to correct: the verified Rexroth configuration uses 2X, not 23.

The two versions use different nominal sizes and flow ratings:

• 4WREE 6 E16: NG6, 16 L/min rated flow
• 4WREE 10 E25: NG10, 25 L/min rated flow

The 4WREE platform provides NG6 rated-flow configurations of 4, 8, 16 and 32 L/min, and NG10 configurations of 25, 50 and 75 L/min.

Our replacement solutions focus on in-situ interchangeability and 100% simulated operating-condition testing.

Technical Specifications

4WREE 10 E25-2X/G24K31/A1V

• Manufacturer: Bosch Rexroth
• Series: 4WREE
• Full Model: 4WREE 10 E25-2X/G24K31/A1V
• Material Number: R900933073
• Product Type: Direct-operated proportional directional valve
• Actuation: Proportional solenoid
• Position Feedback: Electrical position feedback
• Electronics: Integrated electronics (OBE)
• Nominal Size: NG10
• Spool Symbol: E
• Rated Flow: 25 L/min
• Rated Flow Test Condition: Δp = 10 bar
• Maximum Operating Pressure: 315 bar
• Maximum Flow: 180 L/min
• Component Series: 2X
• Supply Voltage: 24 VDC
• Electrical Connection: K31
• Command Interface: A1
• Command Input: ±10 V
• Seal Material: FKM
• Mounting: Subplate mounting
• Mounting Standard: ISO 4401
• Main Ports: 4
• Switching Positions: 3
• Displacement: Not applicable
• Maximum Rotational Speed: Not applicable.

4WREE 6 E16-2X/G24K31/A1V-655

• Manufacturer: Bosch Rexroth
• Series: 4WREE
• Full Model: 4WREE 6 E16-2X/G24K31/A1V-655
• Material Number: R900950342
• Product Type: Direct-operated proportional directional valve
• Actuation: Proportional solenoid
• Position Feedback: Electrical position feedback
• Electronics: Integrated electronics (OBE)
• Nominal Size: NG6
• Spool Symbol: E
• Rated Flow: 16 L/min
• Rated Flow Test Condition: Δp = 10 bar
• Maximum Operating Pressure: 315 bar
• Maximum Flow: 80 L/min
• Component Series: 2X
• Supply Voltage: 24 VDC
• Electrical Connection: K31
• Command Interface: A1
• Command Input: ±10 V
• Seal Material: FKM
• Mounting: Subplate mounting
• Mounting Interface: ISO 4401-03-02-0-05
• NFPA Interface: NFPA T3.5.1 R2-2002 D03
• Main Ports: 4
• Switching Positions: 3
• Electrical Connector: 7-pole, 6 + PE
• Supply Voltage Range: 19.4–35 VDC
• Maximum Amplifier Current: 2 A
• Impulse Current: 3 A
• Duty Cycle: 100%
• Maximum Coil Temperature: 150°C
• Protection: IP65 with mating connector properly mounted and locked
• Weight: 2.45 kg
• Displacement: Not applicable
• Maximum Rotational Speed: Not applicable.

Model Code Clarification: 4WREE6E16-23 vs. 2X

The original title contains:

4WREE6E16-23/G24K31/A1V-655

The verified Rexroth configuration corresponding to R900950342 is:

4WREE 6 E16-2X/G24K31/A1V-655

The 2X designation identifies the 20–29 component series, for which the installation and connection dimensions remain unchanged within the series.

The remaining codes can be identified as:

• E16: E spool, 16 L/min rated flow
• G24: 24 VDC
• K31: DIN EN 175201-804 electrical connector
• A1: ±10 V command input
• V: FKM seals

The -655 suffix is retained as part of the complete verified model, but no sufficiently reliable public documentation was found to assign an additional independent engineering meaning to 655. It should therefore not be expanded speculatively.

Key Technical Advantages

1. Direct-Operated Proportional Control

The 4WREE uses direct proportional solenoid actuation to continuously position the control spool.

The valve therefore regulates both hydraulic flow direction and flow magnitude rather than operating only as an on/off directional valve.

2. Electrical Spool-Position Feedback

The integrated position feedback system monitors actual spool movement.

The Rexroth structure identifies the proportional solenoid together with an inductive position transducer, providing the feedback required for accurate proportional spool control.

3. Integrated OBE Electronics

The WREE configuration integrates valve electronics into the valve assembly.

Rexroth distinguishes the WRE version, which uses external control electronics, from WREE, which uses integrated electronics.

4. NG6 and NG10 Platform Options

The 4WREE family is available in two principal sizes:

• NG6: 4, 8, 16 and 32 L/min rated-flow versions
• NG10: 25, 50 and 75 L/min rated-flow versions.

This provides engineering flexibility while retaining the same proportional-control architecture.

5. 315 Bar Maximum Operating Pressure

The 4WREE platform is specified for a maximum operating pressure of 315 bar.

The pressure rating should be considered separately from nominal flow and actual pressure-drop requirements.

6. High Maximum Flow Capacity

For the specific configurations:

4WREE 6 E16

• Rated flow: 16 L/min
• Maximum flow: 80 L/min.

4WREE 10 E25

• Rated flow: 25 L/min
• Maximum flow: 180 L/min.

Rated flow should therefore not be interpreted as the absolute physical maximum flow through the valve.

7. 24 VDC / ±10 V Interface

Both specified valves use:

G24 + K31 + A1

meaning 24 VDC supply, K31 electrical connection and ±10 V command input.

This provides a standard interface for industrial analog control systems.

8. FKM Sealing

The V designation specifies FKM seals.

This configuration can be selected for hydraulic applications where FKM sealing is appropriate for the operating fluid and temperature conditions.

Application Areas

Typical applications include:

• Injection molding machines
• Hydraulic presses
• Forming equipment
• Industrial hydraulic power units
• Machine tools
• Automated hydraulic equipment
• Hydraulic cylinder speed control
• Hydraulic cylinder positioning
• Hydraulic motor speed control
• Electro-hydraulic proportional systems
• Hydraulic test equipment
• Precision flow-direction control systems

The NG6 version is suited to lower-flow hydraulic circuits, while the NG10 version addresses higher-flow requirements.

Expert Maintenance Tips

1. Match the Rated-Flow Configuration

The 4WREE 6 E16 and 4WREE 10 E25 are different nominal-size configurations:

• NG6 / 16 L/min
• NG10 / 25 L/min

They should not be assumed to be physically interchangeable simply because both are from the 4WREE family.

2. Verify the ±10 V Command Interface

Both specified models use the A1 interface.

Rexroth defines A1 as a ±10 V command-value input, rather than a 4–20 mA interface.

3. Do Not Confuse Rated Flow With Maximum Flow

For the NG6 E16 model:

16 L/min = rated flow

while:

80 L/min = maximum flow.

Similarly, the NG10 E25 model has 25 L/min rated flow and a platform maximum-flow capability of 180 L/min.

4. Verify the Position-Feedback Circuit

Because 4WREE incorporates electrical spool-position feedback, service checks should include:

command input → spool position → actual-value feedback → hydraulic output

An electrical feedback fault may appear as a hydraulic control problem even when the spool can still move mechanically.

5. Maintain Hydraulic Cleanliness

The precision spool and position-feedback arrangement require appropriate fluid cleanliness.

Before replacing the valve because of unstable flow or poor response, inspect the hydraulic filter, oil condition and contamination level.

6. Check the K31 Seven-Pin Connection

The K31 version uses a 7-pole connector (6 + PE) according to EN 175201-804.

Verify power, command, feedback, reference and protective-earth connections before commissioning.

7. Apply Correct Mounting Torque

For the verified NG6 R900950342 configuration, the published mounting hardware includes M5 × 50, class 10.9 socket-head screws, with a specified tightening torque depending on the screw version.

Mounting torque should not automatically be transferred to other 4WREE sizes without checking the applicable mounting documentation.

8. Perform Full Proportional Functional Testing

After replacement, verify:

24 VDC → ±10 V command → spool movement → actual-value feedback → hydraulic pressure/flow → rated-flow performance → leakage

Our OEM replacement program can additionally apply 100% simulated operating-condition testing to verify proportional response, feedback behavior, hydraulic performance and in-situ interchangeability.