Product Overview
The DFA-02-3C2-A220-35C, DFA-02-2D2-A220-35C, and DFA-02-3C2-A220-35C-11H are core models in the Taiwan DOFLUID DFA series of wet-type solenoid directional valves, G02 size (1/4 inch), with mounting pattern conforming to NG6 / CETOP 3 / NFPA D03 standards. The DFA series delivers an exceptional combination of 35 MPa (350 bar / 5,000 psi) high pressure and 160 L/min (42 GPM) high flow capacity. Constructed from high-strength cast iron, the valve body delivers superior rigidity and fatigue resistance.
DFA, DFB, and DFC are sub-series within the same product family, sharing identical mounting dimensions and performance specifications—differing primarily in electrical connection methods:
DFA Series: Hirschmann/DIN type connector
DFB Series: Terminal box type connection
DFC Series: Lead wire type connection
DFA-02-3C2-A220-35C / DFA-02-3C2-A220-35C-11H:
Both models are 4-way, 3-position solenoid directional valves featuring spring centered configuration. The spool type is 3C2 — all ports blocked in neutral position (closed center). Double solenoid operation, with the spool automatically returning to neutral by spring force when de-energized. This is the most widely used standard valve configuration in industrial hydraulic systems. The 11H suffix on DFA-02-3C2-A220-35C-11H denotes a specific coil configuration option.
DFA-02-2D2-A220-35C:
The DFA-02-2D2-A220-35C is a 4-way, 2-position solenoid directional valve featuring spring offset configuration. The spool type is 2D2. Single solenoid operation—when de-energized, the spool returns to the initial position by spring force.
Model Code Breakdown (using DFA-02-3C2-A220-35C as an example):
DFA: Wet-Type Solenoid Directional Valve Series (DIN type connector)
02: G02 Size (1/4 inch, NG6 / CETOP 3)
3C2 / 2D2: Spool Type (3C2=4-way 3-position spring centered, closed center; 2D2=4-way 2-position spring offset)
A220: Coil Voltage (AC220V, 50/60Hz)
35C: Design Code (35=high-pressure high-flow type, allowable back pressure 160 bar; C=with cover type)
11H: Specific coil configuration option
As original DOFLUID DFA series solenoid directional valves, these products offer complete interchangeability within the same series and size, requiring no modifications to mounting interfaces or piping layouts.
Technical Specifications
DFA-02 Series Common Specifications:
Brand: DOFLUID (Taiwan)
Series: DFA Series
Product Type: Wet-Type Solenoid Directional Valve
Nominal Size: G02 (1/4 inch)
Mounting Standard: NG6 / CETOP 3 / NFPA D03
Maximum Operating Pressure: 35 MPa (350 bar / 5,000 psi)
Maximum Flow Rate: 160 L/min (42 GPM)
Allowable Back Pressure: 16 MPa (160 bar)
Maximum Shifting Frequency: ≥180 cycles/min
Protection Class: IP65 (with properly installed connector)
Insulation Class: Class H
Compatible Fluids: Petroleum-based hydraulic oil
Solenoid Type: Wet-Type (Oil-Immersed Armature)
Operating Temperature Range: -20°C to +70°C
Viscosity Range: 15–400 mm²/s
Mounting Type: Subplate Mounting
DFA-02-3C2-A220-35C Specifications:
Model: DFA-02-3C2-A220-35C
Spool Configuration: 4-way, 3-position
Spring Arrangement: Spring Centered
Spool Type: 3C2 (all ports blocked in neutral)
Coil Voltage: AC220V (50/60Hz)
Electrical Connection: Hirschmann/DIN Type Connector
Design Code: 35C
Weight: Approx. 2.2–2.8 kg
DFA-02-2D2-A220-35C Specifications:
Model: DFA-02-2D2-A220-35C
Spool Configuration: 4-way, 2-position
Spring Arrangement: Spring Offset
Spool Type: 2D2
Coil Voltage: AC220V (50/60Hz)
Electrical Connection: Hirschmann/DIN Type Connector
Design Code: 35C
Weight: Approx. 2.2–2.8 kg
DFA-02-3C2-A220-35C-11H Specifications:
Model: DFA-02-3C2-A220-35C-11H
Spool Configuration: 4-way, 3-position
Spring Arrangement: Spring Centered
Spool Type: 3C2
Coil Voltage: AC220V (50/60Hz)
Electrical Connection: Hirschmann/DIN Type Connector with 11H coil configuration
Design Code: 35C
Weight: Approx. 2.2–2.8 kg
Key Technical Advantages
1. High-Pressure High-Flow Performance
The DFA-02 series delivers an exceptional combination of 35 MPa (5,000 psi) operating pressure and 160 L/min (42 GPM) flow capacity. Allowable back pressure at the tank port reaches 16 MPa (160 bar) . This performance places it at the forefront of NG6 size solenoid directional valves, suitable for demanding high-pressure, high-flow hydraulic systems.
2. Wet-Type (Oil-Immersed) Solenoid Design for Quiet, Long-Life Operation
The DFA series features wet-type (oil-immersed) armature design—the movable iron core operates fully submerged in hydraulic oil. The hydraulic oil lubricates moving parts to reduce wear and cushions switching impact and vibration. This design ensures stable and quiet operation under high-pressure and high-frequency conditions, significantly extending valve service life.
3. Dual Return Flow Path Design — Reduced Pressure Drop and Heat Generation
The dual return flow path design substantially reduces return line pressure drop and minimizes system temperature rise. This optimization improves system efficiency and reduces operating costs.
4. Low Voltage Surge and Quiet Operation with AC/DC Coils
AC/DC coils feature reduced voltage surge characteristics, providing quieter operation and extended relay contact life. Optional surge-free coils further suppress voltage spikes to protect control systems.
5. Integrated Coil Design for Superior Environmental Resistance
Coils feature integrated molded construction, delivering excellent moisture resistance, heat dissipation, and high-temperature performance. IP65 protection is achieved with properly installed connector, effectively resisting dust and water ingress for demanding industrial and mobile equipment applications.
6. International Standard Compliance for Global Interchangeability
Mounting conforms to NG6 / CETOP 3 / NFPA D03 international standards. Fully compatible with globally adopted NG6 size interfaces for direct replacement of same-series, same-specification products.
Application Areas
DFA-02-3C2-A220-35C / DFA-02-3C2-A220-35C-11H (4-way, 3-position, spring centered):
Injection Molding Machinery — Directional control for clamping, injection, and ejection cylinders
Hydraulic Presses and Forging Equipment — Directional control for presses and forming equipment
CNC Machine Tools — Directional control for machine tool hydraulic systems
Die-Casting Machines — Directional control for high-pressure casting equipment
Hydraulic Punching Machines — Directional control for punching equipment
Vulcanizing Presses — Hydraulic control for rubber vulcanizing equipment
Industrial Automation Production Lines — Hydraulic actuator control for automated production lines
DFA-02-2D2-A220-35C (4-way, 2-position, spring offset):
Hydraulic Power Units (HPU) — Directional control and flow switching
Unloading Circuits — System unloading and pressure release control
Material Handling Equipment — Hydraulic control for forklifts and lifting platforms
Safety Interlock Devices — Control circuits that automatically return to a safe state when de-energized
Expert Maintenance Tips
1. Installation Guidelines
DFA-02 series mounting must conform to NG6 / CETOP 3 / NFPA D03 standards.
Thoroughly clean the mounting surface and all ports (P, A, B, T) before installation to prevent foreign particles from entering and causing spool sticking or seal damage.
Tighten mounting bolts evenly to the specified torque to ensure proper sealing between the valve body and mounting surface.
DFA-02 is G02 size (1/4 inch, NG6); DFA-03 is G03 size (3/8 inch, NG10)—verify size compatibility during selection.
2. Hydraulic Fluid Cleanliness
Recommended fluid: Petroleum-based hydraulic oil. For other fluid types, verify seal material compatibility.
Install a return line filter with minimum 10 μm filtration rating upstream of the valve.
3. Electrical Connection Specifications
All three models use AC220V (50/60Hz) supply. Verify supply voltage matches coil rated voltage before connection.
Connector standard: Hirschmann/DIN type. Ensure the connector is fully locked to achieve IP65 protection.
The 11H suffix on DFA-02-3C2-A220-35C-11H denotes a specific coil configuration—refer to coil nameplate markings during wiring.
4. Back Pressure Control
DFA-02 series (35C design code) return line back pressure must not exceed 16 MPa (160 bar) . If back pressure is excessive, consider using a dedicated return line or routing the valve return port directly to the tank.
The dual return flow path design effectively reduces return line pressure drop.
5. Periodic Maintenance Inspection
Inspect the valve body for external oil leakage every 2,000 operating hours or at least annually.
Check electrical connectors for looseness, oxidation, or moisture ingress.
Wet-type solenoid coils can be replaced quickly without disturbing hydraulic connections.
If response lag or unstable shifting is observed, first check system fluid cleanliness and verify the spool is not sticking.
