Product Overview

The 4WE6D61/EW220RNZ5L and 4WE6D70/HG24N9K4 are Bosch Rexroth WE6 direct-operated solenoid directional spool valves designed for hydraulic flow switching and actuator directional control.

The WE6 family is a direct-operated solenoid directional spool-valve platform with a standardized NG6 / ISO 4401-03 / CETOP 03 mounting interface. The platform is rated for up to 350 bar, while maximum flow depends on the electrical configuration and spool arrangement. Published WE6 data distinguish 80 L/min maximum for DC configurations and 60 L/min for AC configurations.

The two models have different electrical and series configurations:

4WE6D61/EW220RNZ5L

• D spool
• Series 61
• 220 VAC with rectifier
• Concealed manual override
• Large right-angle plug with indicator lamp

4WE6D70/HG24N9K4

• D70 spool
• 7X series
• 24 VDC
• Concealed manual override
• K4 electrical connection
• Rexroth material number R901087088.

For replacement applications, the complete configuration must be matched rather than selecting solely by the “4WE6” family name.

Our replacement program focuses on in-situ interchangeability and 100% simulated operating-condition testing.

Technical Specifications

4WE6D61/EW220RNZ5L

• Manufacturer: Bosch Rexroth
• Series: WE6
• Full Model: 4WE6D61/EW220RNZ5L
• Product Type: Direct-operated solenoid directional spool valve
• Nominal Size: NG6 / Size 6
• Mounting Standard: ISO 4401-03 / CETOP 03
• Spool Symbol: D
• Component Series: 61
• Actuation: Single solenoid with spring return
• Solenoid: Wet-pin type with detachable coil
• Supply: 220 VAC with rectifier
• Manual Override: Concealed manual override
• Connector: Z5L, large right-angle connector with indicator lamp
• Maximum Pressure P/A/B: 350 bar
• Maximum Flow, AC Configuration: 60 L/min
• Maximum T-Port Pressure: 210 bar
• Fluid: Mineral oil hydraulic fluids
• Viscosity: approximately 2.8–500 mm²/s
• Cleanliness: ISO 4406(c) Class 20/18/15
• Duty Cycle: 100%
• Control: Direct solenoid actuation
• Displacement: Not applicable
• Maximum Rotational Speed: Not applicable.

No sufficiently reliable public source was found during this verification to assign a specific Rexroth R9 material number to the complete historical 4WE6D61/EW220RNZ5L ordering code, so none is provided here.

4WE6D70/HG24N9K4

• Manufacturer: Bosch Rexroth
• Series: WE6
• Full Model: 4WE6D70/HG24N9K4
• Material Number: R901087088
• Product Type: Direct-operated solenoid directional spool valve
• Nominal Size: NG6 / Size 6
• Mounting Interface: ISO 4401-03-02-0-05 / CETOP 03
• Spool Symbol: D70
• Component Series: 7X
• Solenoid: Wet-pin type
• Supply Voltage: 24 VDC
• Manual Override: N9 concealed manual override
• Electrical Connection: K4
• Maximum Pressure P/A/B: 350 bar
• Maximum T-Port Pressure: 210 bar
• Maximum Flow: 80 L/min
• Hydraulic Fluid: Mineral oil / compatible hydraulic fluids
• Viscosity: approximately 2.8–500 mm²/s
• Installation Position: Any
• Control: Direct solenoid operation
• Displacement: Not applicable
• Maximum Rotational Speed: Not applicable.

Key Technical Advantages

1. Direct-Operated Spool Architecture

The WE6 uses a direct solenoid-to-spool operating principle.

This provides a straightforward hydraulic directional-control architecture without a separate pilot stage and is widely applicable to industrial hydraulic circuits.

2. 350 Bar Pressure Capability

The WE6 platform supports a maximum pressure of 350 bar.

This allows the valve family to serve demanding industrial hydraulic circuits, provided the actual flow and return-pressure limits are respected.

3. Different AC and DC Flow Ratings

Published WE6 data distinguish:

• DC maximum flow: 80 L/min
• AC maximum flow: 60 L/min.

This distinction is particularly important when selecting or replacing the W220R AC version versus the HG24 DC version.

4. Wet-Pin Solenoid Design

The WE6 uses wet-pin solenoid technology.

The hydraulic environment around the armature supports heat transfer and contributes to a durable solenoid arrangement.

5. Detachable Coils

The solenoid coils can be removed and replaced, supporting practical field maintenance and reducing unnecessary complete-valve replacement.

6. Standard NG6 / CETOP 03 Interface

The ISO 4401-03 mounting interface makes WE6 valves suitable for standardized manifolds, CETOP subplates and modular hydraulic assemblies.

7. Distinct Electrical Configurations

The two specified valves demonstrate the flexibility of the WE6 platform:

• 4WE6D61/EW220RNZ5L: 220 VAC rectified
• 4WE6D70/HG24N9K4: 24 VDC.

This allows the same basic hydraulic platform to be integrated into different industrial control architectures.

Application Areas

Typical applications include:

• Industrial hydraulic power units
• CNC machine tools
• Metal-processing machinery
• Injection molding machines
• Hydraulic presses
• Automated production equipment
• Hydraulic clamping systems
• Hydraulic cylinder directional control
• Hydraulic motor start/stop and reversing circuits
• Hydraulic test equipment
• Auxiliary hydraulic circuits

The AC 4WE6D61 is suited to control systems using 220 VAC rectified solenoids, while the 4WE6D70 is suited to 24 VDC control architectures.

Expert Maintenance Tips

1. Match the Exact Spool Symbol

The D and D70 configurations define the hydraulic flow paths.

The hydraulic symbol should always be compared with the original valve before replacement.

2. Do Not Treat W220R and HG24 as Equivalent

W220R = 220 VAC with rectifier, while HG24 = 24 VDC.

These are different electrical architectures and cannot be interchanged without redesigning the control circuit.

3. Observe the AC Flow Limit

For AC WE6 configurations, the published maximum flow is 60 L/min, rather than the 80 L/min DC figure.

4. Check 24 VDC Supply Quality on the D70 Version

For 4WE6D70/HG24N9K4, inspect the 24 VDC power supply, voltage drop, wiring and K4 connector when switching becomes unreliable.

5. Control T-Port Back Pressure

The published WE6 T-port maximum pressure is 210 bar.

Return-line restrictions and excessive common-return pressure should therefore be avoided.

6. Inspect the Manual Override

The specified configurations include manual override arrangements. Confirm that the valve is depressurized or operated within the applicable manufacturer’s pressure limits before using the emergency override.

7. Keep the Mounting Surface Clean

Inspect the ISO 4401 mounting face, O-rings, fastening screws and hydraulic ports before installation.

8. Perform Full Functional Testing

After replacement, verify:

Electrical activation → spool shifting → P/A/B/T pressure → directional function → leakage → operating-cycle performance

For OEM replacement projects, our 100% simulated operating-condition testing can verify hydraulic function, electrical compatibility and in-situ interchangeability before shipment.