DFA-02-3C9 DOFLUID Solenoid Valve 350 Bar

Product Overview

The DOFLUID DFA-02-3C9 / DFA-02-3C10 is a direct-operated wet-pin solenoid directional valve for industrial hydraulic flow-direction control.

DOFLUID’s official website categorizes the DFA/B family as hydraulic solenoid directional valves and separately lists proportional directional and pressure-control products. The manufacturer also provides historical electronic catalogs, including a dedicated catalog section for wet solenoid directional valves.

The supplied title contains two distinct spool configurations:

• DFA-02-3C9
• DFA-02-3C10

Both belong to the DFA-02 platform, but they must not be treated as identical valves with different coil voltages.

Published product data identify:

• DFA-02-3C9: 4/3 directional configuration, up to 100 L/min, 350 bar.
• DFA-02-3C10: 4/3 directional configuration, up to 50 L/min, 350 bar.

The published spool information identifies 3C9 with a regenerative / P-AB-center function, while 3C10 is listed with a B-T-open / P-A-closed center function. This difference directly affects actuator behavior and therefore must be matched to the original hydraulic schematic during replacement.

The DFA-02 family is available with multiple coil voltages, including 24 VDC, 110 VAC and 220 VAC, as reflected in published product catalogs.

Technical Specifications

DFA-02-3C9

• Model: DFA-02-3C9
• Brand: DOFLUID
• Product Type: Direct-operated solenoid directional valve
• Construction: Wet-pin solenoid directional spool valve
• Series: DFA-02
• Nominal Size: NG6
• Interface: CETOP 03 / ISO 4401-03 class
• Valve Function: 4/3 directional control
• Solenoid Configuration: Double solenoid
• Spool Code: 3C9
• Maximum Operating Pressure: 350 bar
• Maximum Flow: 100 L/min
• Center Function: Regenerative / P-AB center
• Actuation: Direct electromagnetic spool actuation
• Available Coil Voltages: 12 VDC, 24 VDC, 110 VAC and 220 VAC family configurations; the supplied title specifically covers 24 VDC, 110 VAC and 220 VAC.
• Mounting: Subplate mounting
• Hydraulic Medium: Hydraulic oil / mineral-oil service
• Displacement: Not applicable
• Maximum Speed: Not applicable
• Peak Pressure: No separate peak-pressure rating is defined in the available documentation; engineering selection should use the 350 bar maximum operating pressure.
• Weight: Exact weight for the complete specified voltage configuration is not sufficiently verified in currently accessible documentation and is therefore not stated.

DFA-02-3C10

• Model: DFA-02-3C10
• Brand: DOFLUID
• Product Type: Direct-operated solenoid directional valve
• Construction: Wet-pin solenoid directional spool valve
• Series: DFA-02
• Nominal Size: NG6
• Interface: CETOP 03 / ISO 4401-03 class
• Valve Function: 4/3 directional control
• Solenoid Configuration: Double solenoid
• Spool Code: 3C10
• Maximum Operating Pressure: 350 bar
• Maximum Flow: 50 L/min
• Center Function: B-T open / P-A closed
• Actuation: Direct electromagnetic spool actuation
• Available Coil Voltages: 12 VDC, 24 VDC, 110 VAC and 220 VAC family configurations; the supplied title covers 24 VDC, 110 VAC and 220 VAC.
• Mounting: Subplate mounting
• Hydraulic Medium: Hydraulic oil / mineral-oil service
• Displacement: Not applicable
• Maximum Speed: Not applicable
• Peak Pressure: No separate official peak-pressure value is identified; maximum operating pressure is 350 bar.
• Weight: Exact complete-model weight is not sufficiently verified in accessible documentation and is therefore not stated.

Common DFA-02 Engineering Characteristics

• Brand: DOFLUID
• Series: DFA-02
• Nominal Size: NG6
• Mounting Interface: CETOP 03
• Maximum Pressure Rating: 350 bar
• Coil Options: 12 VDC, 24 VDC, 110 VAC, 220 VAC and related configurations.
• Control Method: Electromagnetic on/off directional control
• Valve Type: Directional spool valve
• Hydraulic Fluid: Hydraulic oil
• Displacement: Not applicable
• Maximum Rotational Speed: Not applicable
• Spool Options: Multiple 2-position and 3-position hydraulic functions
• Flow Rating: Spool-dependent; it must not be generalized across the entire DFA-02 series.

Key Technical Advantages

1. Direct-operated solenoid architecture

The DFA-02 uses direct solenoid actuation of the main hydraulic spool.

Compared with a pilot-operated valve, the direct architecture is compact and provides a relatively simple actuation chain for NG6/CETOP 03 hydraulic circuits. DOFLUID officially categorizes the DFA/B products as wet solenoid directional valves.

2. 350 bar high-pressure capability

Published DFA-02 product data specify a maximum operating pressure of 350 bar.

This provides a suitable pressure class for demanding industrial hydraulic circuits.

The 350 bar value should be treated as the specified maximum operating limit rather than a statement that every spool can continuously operate at maximum flow and maximum pressure simultaneously.

3. Different hydraulic behavior through 3C9 and 3C10 spools

The two configurations provide significantly different center functions:

• 3C9: regenerative / P-AB center
• 3C10: B-T open / P-A closed.

This affects actuator regeneration, pressure unloading and neutral-state hydraulic behavior.

4. 100 L/min capability for 3C9

Published product data specify up to 100 L/min for DFA-02-3C9.

The higher flow capability makes 3C9 appropriate for applications requiring greater actuator flow, while 3C10 has a published 50 L/min rating.

Therefore, the correct SEO approach is to associate the flow rating with the specific spool code rather than claiming 100 L/min for the entire DFA-02 family.

5. Standard NG6 / CETOP 03 interface

The DFA-02 platform is based on the standard NG6/CETOP 03 size.

This facilitates integration into hydraulic manifolds, modular valve stations and existing industrial hydraulic equipment.

6. Multiple electrical configurations

The DFA-02 family supports several coil-voltage configurations, including:

• 12 VDC
• 24 VDC
• 110 VAC
• 220 VAC.

This allows the same hydraulic platform to serve machines with different control-voltage architectures.

7. Wet-pin solenoid construction

The wet-pin solenoid architecture places the moving armature within the hydraulic environment and can support effective heat transfer during operation.

Correct oil viscosity and contamination control remain essential for maintaining reliable spool and armature movement.

8. OEM replacement and interchangeability engineering

For DFA-02-3C9 and DFA-02-3C10 replacement programs, the critical matching criteria include:

• NG6 / CETOP 03 mounting
• spool symbol
• P/A/B/T flow logic
• 350 bar pressure class
• spool-specific flow capacity
• coil voltage
• electrical connection
• sealing compatibility

Our replacement engineering can target both mechanical and functional Interchangeability, followed by 100% simulated operating-condition testing for switching behavior, pressure, flow and continuous operation.

Application Areas

DFA-02-3C9

Typical applications include:

• Hydraulic-cylinder regenerative circuits
• Hydraulic presses
• Hydraulic clamping systems
• Rapid-feed mechanisms
• Injection-molding auxiliary circuits
• Industrial hydraulic power units
• Regenerative actuator circuits
• OEM hydraulic manifolds

DFA-02-3C10

Typical applications include:

• Industrial hydraulic power units
• Hydraulic lifting systems
• Actuator directional control
• Machine-tool auxiliary hydraulics
• Clamping and release circuits
• Automated hydraulic machinery
• Metalworking equipment
• OEM hydraulic control cabinets

The final selection must always be based on the machine hydraulic schematic.

Expert Maintenance Tips

1. Do not treat 3C9 and 3C10 as interchangeable

Although both belong to DFA-02 / NG6 / CETOP 03, their center functions and flow ratings differ.

Published data specify:

• 3C9: 100 L/min
• 3C10: 50 L/min.

The complete spool code must therefore remain part of the replacement part number.

2. Match the coil voltage exactly

The DFA-02 family includes:

• 24 VDC
• 110 VAC
• 220 VAC

and other coil configurations.

The hydraulic valve body may be identical across variants, but the electrical coil is not automatically interchangeable.

3. Do not interpret 350 bar as an unrestricted system value

Commissioning should verify:

• P pressure
• A/B working pressure
• T back pressure
• actual flow
• valve pressure drop

Published DFA-family data also show a back-pressure reference around 210 bar, so the return circuit must be evaluated as part of the hydraulic design.

4. Control hydraulic contamination

Particle contamination can increase spool friction and lead to:

• slow shifting
• incomplete spool movement
• unstable neutral operation
• increased internal leakage
• abnormal pressure drop

A proper filtration and oil-maintenance program is therefore essential.

5. Protect the CETOP mounting interface

During replacement:

• Clean the CETOP mounting face
• Inspect all O-rings
• Check mounting threads
• Inspect the valve block surface
• Keep ports free of contamination
• Confirm secure fastening

This is particularly important on older machinery where the manifold surface may have been repeatedly serviced.

6. Perform dynamic functional testing

After installation, verify:

• correct coil voltage
• solenoid switching
• 3C9 or 3C10 center function
• P-to-A / P-to-B switching
• A/B-to-T return paths
• operating pressure
• actual flow
• repeated switching
• thermal stability

For OEM replacement products, 100% simulated operating-condition testing should be completed before shipment rather than relying only on a static continuity check.