Product Overview

The Sun Hydraulics CXFA Series consists of 2-port free-flow nose-to-side cartridge check valves designed to permit free flow in one direction while blocking reverse flow.

For the primary model CXFA-XCN, the flow path is:

Port 1 → Port 2: Free Flow

Port 2 → Port 1: Blocked

The CXFA family uses a T-5A cavity, provides 40 GPM / 160 L/min nominal capacity, accepts up to 5000 psi / 350 bar at Ports 1 and 2, and has a maximum leakage specification of approximately 0.07 cc/min at 24 cSt.

The CXFA-XCN configuration uses a 30 psi / 2 bar cracking pressure and Buna-N seal.

Technical Specifications

CXFA-XCN

• Manufacturer: Sun Hydraulics
• Series: 2
• Product Type: 2-port free-flow nose-to-side check valve
• Model: CXFA-XCN
• Cavity: T-5A
• Nominal Capacity: 40 GPM / 160 L/min
• Flow Direction: Port 1 → Port 2
• Reverse Flow: Blocked
• Control: X — Non-adjustable
• Cracking Pressure: 30 psi / 2 bar
• Seal: Buna-N
• Maximum Operating Pressure: 5000 psi / 350 bar at Ports 1 and 2
• Maximum Valve Leakage: 0.07 cc/min at 24 cSt
• Valve Hex Size: 1-1/8 in / 28.6 mm
• Installation Torque: 45–50 lbf·ft / 60–70 Nm
• Model Weight: 0.41 lb / 0.19 kg
• Pump Displacement: Not applicable
• Pump Rated Pressure: Not applicable
• Pump Peak Pressure: Not applicable
• Maximum Pump Speed: Not applicable
• Control Method: Mechanical spring-loaded check operation
• Primary Function: One-way flow and reverse-flow blocking

CXFA Variant Configuration

Sun’s CXFA ordering structure follows:

CXFA – X [Cracking Pressure] [Seal]

Cracking Pressure Codes

• A: 4 psi / 0.3 bar
• B: 15 psi / 1 bar
• C: 30 psi / 2 bar
• D: 50 psi / 3.5 bar
• E: 75 psi / 5 bar
• F: 100 psi / 7 bar
• Z: 1 psi / 0.07 bar

Seal Codes

• N: Buna-N
• V: Viton
• E: EPDM

This produces the requested variants:

• CXFA-XBV: 15 psi / 1 bar + Viton
• CXFA-XCN: 30 psi / 2 bar + Buna-N
• CXFA-XDN: 50 psi / 3.5 bar + Buna-N
• CXFA-XEN: 75 psi / 5 bar + Buna-N
• CXFA-XEV: 75 psi / 5 bar + Viton

Key Technical Advantages

1. 40 GPM / 160 L/min Capacity

The CXFA Series 2 cartridge provides a nominal capacity of:

40 GPM / 160 L/min

This makes it suitable for medium-to-high-flow hydraulic circuits using a T-5A cartridge architecture.

2. 350 bar High-Pressure Capability

The valve can accept up to:

5000 psi / 350 bar

at both primary ports.

This supports high-pressure industrial and mobile hydraulic systems.

3. Very Low Valve Leakage

Sun specifies maximum valve leakage of approximately:

0.07 cc/min at 24 cSt

This low leakage is valuable for pressure isolation and hydraulic circuit separation.

4. Fixed Cracking Pressure

CXFA valves are non-adjustable.

Cracking pressure is determined by the selected internal spring configuration.

This provides defined behavior for each complete model code.

5. T-5A Cartridge Architecture

CXFA-XCN uses the T-5A cavity, enabling compact manifold and actuator integration.

Sun’s line-mount documentation also shows CXFA cartridges integrated into T-5A bodies.

6. Floating Construction

Sun’s floating construction is designed to minimize internal binding resulting from excessive installation torque or cavity/cartridge machining variation.

7. Multiple Seal Options

The CXFA family supports:

• Buna-N
• Viton
• EPDM

This allows the cartridge to be selected according to hydraulic-fluid and environmental requirements.

Sun notes that EPDM configurations are intended for phosphate-ester fluids and can be damaged by petroleum-based fluids, greases and lubricants.

Engineering Materials and Manufacturing

The publicly available Sun documentation confirms standard material/coating configurations and multiple seal choices, but does not provide complete alloy, heat-treatment and hardness specifications for every internal CXFA component.

Therefore, specific material grades should not be presented as OEM data without supporting documentation.

The most important engineering manufacturing factors are:

Poppet and Seat Geometry

These determine shut-off leakage and reseating behavior.

Spring Calibration

The internal spring configuration determines cracking pressure.

Alignment

Stable poppet/seat alignment is essential for repeatable opening and closing.

Surface Finish

Internal surface condition influences friction, wear and contamination sensitivity.

Seal Integrity

The correct seal material is essential for fluid compatibility and long-term reliability.

Application Areas

Typical CXFA applications include:

• Hydraulic cylinders
• Lift and clamp circuits
• Mobile hydraulic systems
• Construction machinery
• Agricultural equipment
• Material-handling equipment
• Hydraulic manifolds
• Machine tools
• Hydraulic presses
• Auxiliary pilot circuits
• Industrial automation systems
• Hydraulic test equipment

The compact cartridge architecture is particularly suitable for integrated manifold applications.

CXFA vs. Other Sun Valve Functions

CXFA-XCN

Free-Flow Nose-to-Side Check Valve

Function:

One-Way Flow + Reverse Blocking

CXED-XCN

Free-Flow Side-to-Nose Check Valve

The primary flow direction is reversed relative to CXFA.

CKCB-XCN

Pilot-to-Open Check Valve

Primarily intended for:

Load Locking / Load Holding

Counterbalance Valve

Primarily intended for:

Overrunning Load Control + Controlled Lowering

Therefore:

CXFA ≠ CXED ≠ CKCB ≠ Counterbalance Valve

Correct functional identification is essential for replacement selection.

Expert Maintenance Tips

1. Verify Flow Direction

For CXFA:

Port 1 → Port 2 = Free Flow

Port 2 → Port 1 = Blocked

If the application requires the opposite flow direction, verify whether a side-to-nose cartridge such as CXED is required.

2. Verify the T-5A Cavity

Before installation, inspect:

• Cavity condition
• Thread condition
• Locating shoulder
• Seal surfaces
• Hydraulic cleanliness
• Mechanical damage

3. Match Cracking Pressure

Do not assume every CXFA has the same cracking pressure.

The requested variants are:

CXFA-XBV → 15 psi

CXFA-XCN → 30 psi

CXFA-XDN → 50 psi

CXFA-XEN → 75 psi

CXFA-XEV → 75 psi

4. Distinguish XEN From XEV

Both use the same 75 psi / 5 bar cracking pressure, but:

• XEN = Buna-N
• XEV = Viton

This difference can be critical when hydraulic-fluid or temperature compatibility is involved.

5. Control Installation Torque

For CXFA-XCN, the specified installation torque is:

45–50 lbf·ft / 60–70 Nm

Avoid excessive torque because installation forces can affect cartridge behavior.

6. Maintain Hydraulic Cleanliness

Contamination can damage the seat or interfere with check-element movement.

For abnormal downstream pressure decay, inspect:

Seat + Poppet + Hydraulic Cleanliness

before replacing the entire manifold.