Product Overview

The Sun Hydraulics CKGB-XCN is a pilot-to-open check valve designed for hydraulic load holding, actuator isolation and controlled reverse flow.

Sun Hydraulics specifies the CKGB as a 240 L/min / approximately 60 GPM pilot-operated check valve installed in a T-17A cavity. The family uses a 3:1 pilot ratio, while the XCN configuration corresponds to a 2.0 bar cracking pressure and Buna-N seal. The maximum operating pressure is 350 bar / 5,000 psi.

Its basic hydraulic function is:

Port 2 → Port 1: Free flow

Port 1 → Port 2: Blocked

Port 3: Hydraulic pilot opening

This makes CKGB suitable for load-locking applications where the actuator must remain hydraulically secured during standstill.

The original product title also includes PBFB, PBDB, FDBA and RDFA products. These are related Sun Hydraulics cartridge valves but perform different hydraulic functions and should not be classified as the same valve:

• PBFB-LAN: Pilot Operated Pressure Reducing Valve
• PBDB-LBN: Pilot Operated Pressure Reducing Valve
• FDBA-LAN: Pressure-Compensated Flow Control Valve with Reverse Flow Check
• RDFA-LCN: Direct-Acting Relief Valve
• CKGB-XCN: Pilot-to-Open Check Valve

For industrial replacement projects, our supplied equivalent solutions can be engineered for in-place interchangeability and subjected to 100% simulated working-condition testing before shipment.

Technical Specifications

CKGB-XCN

• Manufacturer: Sun Hydraulics
• Product Type: Pilot-to-Open Check Valve
• Model Code: CKGB-XCN
• Series: 1
• Cavity: T-17A
• Nominal Capacity: 240 L/min / approximately 60 GPM
• Pilot Ratio: 3:1
• Pilot Configuration: Standard, unsealed pilot
• Control: Standard Pilot
• Cracking Pressure: 2.0 bar / approximately 30 psi
• Seal Material: Buna-N
• Maximum Operating Pressure: 350 bar / 5,000 psi
• Maximum Valve Leakage: 0.07 cc/min at 24 cSt
• Installation Torque: 200–215 Nm
• Flow Direction: Free Port 2 → Port 1; pilot-to-open Port 1 → Port 2
• Adjustment: Non-adjustable cracking-pressure configuration

PBFB-LAN

• Manufacturer: Sun Hydraulics
• Product Type: Pilot Operated Pressure Reducing Valve
• Model: PBFB-LAN
• Cavity: T-2A
• Series: 2
• Nominal Capacity: 20 GPM
• Control: Standard Screw Adjustment
• Adjustment Range: 100–3000 psi
• Maximum Pressure: 5000 psi
• Seal: Buna-N

PBFB-LAN-BCD

• Manufacturer: Sun Hydraulics
• Product Type: Pilot Operated Pressure Reducing Valve Assembly
• Assembly Model: PBFB-LAN-BCD
• Base Cartridge: PBFB-LAN
• Cavity: T-2A
• Nominal Flow: 20 GPM
• Adjustment Range: 100–3000 psi
• Mounting: Inline assembly
• Main Ports: 3/4″ NPT
• Pilot Port: 1/4″ NPT
• Maximum Assembly Pressure: 3000 psi
• Approx. Assembly Weight: 0.8 kg

PBDB-LBN

• Manufacturer: Sun Hydraulics
• Product Type: Pilot Operated Pressure Reducing Valve
• Model: PBDB-LBN
• Cavity: T-11A
• Series: 1
• Nominal Capacity: 40 L/min / 10 GPM
• Control: Standard Screw Adjustment
• Adjustment Range: 3.5–105 bar
• Maximum Operating Pressure: 350 bar
• Seal: Buna-N
• Installation Torque: 41–47 Nm
• Approx. Model Weight: 0.15 kg

FDBA-LAN

• Manufacturer: Sun Hydraulics
• Product Type: Fully Adjustable Pressure-Compensated Flow Control Valve with Reverse Flow Check
• Model: FDBA-LAN
• Cavity: T-13A
• Series: 1
• Nominal Capacity: 23 L/min / 6 GPM
• Control: Standard Screw Adjustment
• Maximum Operating Pressure: 350 bar / 5,000 psi
• Adjustment: 5 turns
• Valve Hex: 22.2 mm / 7/8 in.
• Installation Torque: 41–47 Nm
• Adjustment Screw Hex: 4 mm
• Locknut Hex: 15 mm
• Locknut Torque: 9–10 Nm
• Approx. Model Weight: 0.20 kg
• Flow Function: Adjustable metering with reverse free flow

RDFA-LCN

• Manufacturer: Sun Hydraulics
• Product Type: Direct-Acting Relief Valve
• Model: RDFA-LCN
• Cavity: T-3A
• Series: 2
• Nominal Capacity: 200 L/min / 50 GPM
• Maximum Operating Pressure: 350 bar / 5,000 psi
• Typical Response Time: 2 ms
• Maximum Leakage at Reseat: 0.7 cc/min
• Reseat: Greater than 90% of setting
• Adjustment: 5 turns
• Valve Hex: 28.6 mm
• Installation Torque: 61–68 Nm
• Adjustment Screw Hex: 4 mm
• Locknut Hex: 15 mm
• Locknut Torque: 9–10 Nm
• Approx. Model Weight: 0.25 kg

Displacement, Maximum Speed and Peak Pressure

These products are hydraulic cartridge valves or valve assemblies rather than pumps or hydraulic motors.

• Displacement: Not applicable
• Maximum Speed: Not applicable
• CKGB-XCN Maximum Operating Pressure: 350 bar / 5,000 psi
• PBFB-LAN Maximum Pressure: 5,000 psi
• PBDB-LBN Maximum Operating Pressure: 350 bar
• FDBA-LAN Maximum Operating Pressure: 350 bar
• RDFA-LCN Maximum Operating Pressure: 350 bar
• Peak Pressure: No separate model-specific peak-pressure value is stated here without verified manufacturer documentation.

Key Technical Advantages

1. High-Flow Pilot-to-Open Load Locking

The CKGB-XCN provides approximately 240 L/min / 60 GPM nominal capacity while maintaining the 3:1 pilot-operated check architecture.

It is therefore suitable for high-flow actuator load-locking circuits where reverse movement must remain blocked until a pilot signal is applied.

2. 3:1 Pilot Ratio

CKGB uses a 3:1 pilot ratio, providing a defined relationship between the hydraulic load and the pilot-opening force.

Pilot pressure should be calculated together with actual load pressure, actuator geometry and backpressure conditions.

3. Low Closed-Valve Leakage

The CKGB family specifies a maximum valve leakage of:

0.07 cc/min at 24 cSt

This is particularly important for applications requiring stable actuator positioning during extended standstill periods.

4. T-17A Cartridge Architecture

CKGB-XCN uses the T-17A cavity, enabling direct integration into hydraulic manifolds and compact cartridge-based valve blocks.

This architecture is suitable for OEM machines and retrofit projects where hydraulic packaging space is limited.

5. Pressure-Compensated Flow Control in FDBA

The FDBA-LAN, although a different valve category, combines:

pressure compensation + adjustable metering + reverse free flow

Its sharp-edged orifice design helps reduce flow variation caused by viscosity changes.

6. Fast Direct-Acting Relief Protection

RDFA-LCN uses a direct-acting relief architecture with a typical response time of approximately 2 ms and maximum reseat leakage of 0.7 cc/min.

This makes it suitable for hydraulic pressure-limiting and transient-protection functions.

Application Areas

CKGB-XCN

• Hydraulic Cylinder Load Holding
• Vertical Load Locking
• Hydraulic Presses
• Material Handling Equipment
• Construction Machinery
• Lifting Systems
• High-Flow Hydraulic Manifolds
• Industrial Hydraulic Power Units
• Actuator Position Holding

PBFB / PBDB

• Multi-Pressure Hydraulic Systems
• Industrial Hydraulic Power Units
• Clamping Circuits
• Machine Tools
• Mobile Hydraulic Equipment
• Pilot-Controlled Pressure Regulation

FDBA-LAN

• Hydraulic Cylinder Speed Control
• Meter-In / Meter-Out Circuits
• Mobile Hydraulic Systems
• Industrial Motion Control
• Hydraulic Manifolds

RDFA-LCN

• Hydraulic Overpressure Protection
• Cross-Port Relief Circuits
• Hydraulic Power Units
• Construction Equipment
• Industrial Manifolds
• Load-Holding Protection

Expert Maintenance Tips

1. Verify the T-17A Cavity

For CKGB-XCN, confirm:

CKGB → T-17A

Do not identify the cartridge only by the CKGB family name. Sun Hydraulics uses different cavities for different flow-frame sizes.

2. Match the XCN Cracking Pressure

The CK*B family offers multiple cracking-pressure configurations, including:

• A — 0.3 bar
• B — 1.0 bar
• C — 2.0 bar
• D — 3.5 bar
• E — 5.0 bar
• F — 7.0 bar

Therefore, CKGB-XCN should not be treated as hydraulically identical to other CKGB variants with different cracking-pressure codes.

3. Do Not Classify PBFB or PBDB as Check Valves

The correct product taxonomy is:

PBFB / PBDB → Pressure Reducing Valve

CKGB → Pilot-to-Open Check Valve

FDBA → Pressure-Compensated Flow Control Valve

RDFA → Direct-Acting Relief Valve

This distinction is important for both technical selection and SEO entity accuracy.

4. Record the Original FDBA Adjustment

FDBA-LAN uses five turns of adjustment.

During maintenance, record the original adjustment position and verify the actual flow after installation rather than simply reproducing the previous screw position.

5. Depressurize Before Adjusting RDFA

For RDFA direct-acting relief cartridges, the adjustment screw seals are exposed to system pressure.

Sun Hydraulics specifies that system pressure should be removed before adjustment, followed by re-pressurization and verification of the new setting.

6. Maintain Clean Pilot Circuits

For pilot-operated PBFB and PBDB valves, stable pilot control and clean hydraulic oil are important for repeatable pressure regulation.

Sun Hydraulics notes that pilot-operated reducing valves offer stable pressure/flow behavior and low hysteresis, while direct-acting valves are generally preferred where faster dynamic response is required.