Product Overview

The Sun Hydraulics CKCD Series is a family of pilot-to-open check valves with sealed pilot designed for hydraulic load locking, actuator isolation and controlled reverse flow.

The CKCD is a screw-in cartridge valve installed in a T-11A cavity. Sun Hydraulics specifies the CKCD at 60 L/min / 15 GPM, with a 3:1 pilot ratio, 350 bar / 5,000 psi maximum operating pressure, a sealed pilot, steel seat and non-vented configuration.

The operating principle is:

Port 2 → Port 1: Free flow

Port 1 → Port 2: Blocked

Port 3 pilot pressure: Opens the valve from Port 1 → Port 2

Sun Hydraulics specifically describes pilot-to-open check valves as locking valves rather than motion-control valves. Counterbalance valves should be used where controlled motion of overrunning loads is required.

The models relevant to the supplied title include:

• CKCD-XCN
• CKCD-LCN
• CACG-LGN / CACGLGN
• CABG-LHN / CABGLHN
• CBEH-LKN
• CBEH-LIN

These models should be treated as related Sun Hydraulics cartridge valves rather than one identical valve configuration.

Technical Specifications

CKCD-XCN

• Manufacturer: Sun Hydraulics
• Series: CKCD
• Valve Type: Pilot-to-Open Check Valve with Sealed Pilot
• Model Code: CKCD-XCN
• Cavity: T-11A
• Nominal Capacity: 60 L/min / 15 GPM
• Pilot Ratio: 3:1
• Pilot Configuration: Sealed Pilot
• Vent Configuration: Non-vented
• Control: Standard Pilot
• Cracking Pressure: 2 bar / 30 psi
• Seal Material: Buna-N
• Maximum Operating Pressure: 350 bar / 5,000 psi
• Maximum Valve Leakage: 0.07 cc/min at 24 cSt
• Valve Hex Size: 22.2 mm
• Installation Torque: 41–47 Nm
• Seat: Steel
• Flow: Free Port 2 → Port 1; pilot-to-open Port 1 → Port 2
• Adjustment: None

CKCD-LCN

• Manufacturer: Sun Hydraulics
• Series: CKCD
• Valve Type: Pilot-to-Open Check Valve with Sealed Pilot
• Model Code: CKCD-LCN
• Cavity: T-11A
• Nominal Capacity: 60 L/min / 15 GPM
• Pilot Ratio: 3:1
• Control: Manual Load Release
• Cracking Pressure: 2 bar / 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: 41–47 Nm

The primary difference from CKCD-XCN is the control configuration: L = Manual Load Release, while X = Standard Pilot.

CACG-LGN / CACGLGN

• Valve Type: 5:1 Pilot Ratio Vented Counterbalance Valve
• Cavity: T-11A
• Capacity: 60 L/min / 15 GPM
• Pilot Ratio: 5:1
• Control: Standard Screw Adjustment
• Functional Setting Range: 140–420 bar
• Standard Setting: 280 bar
• Check Cracking Pressure: 2.8 bar
• Maximum Setting: 420 bar
• Maximum Recommended Load Pressure at Maximum Setting: 320 bar
• Maximum Valve Leakage at Reseat: 0.3 cc/min
• Adjustment: 5 turns
• Installation Torque: 40–50 Nm
• Approx. Weight: 0.20 kg
• Seal: Buna-N

CABG-LHN / CABGLHN

• Valve Type: 4.5:1 Pilot Ratio Atmospherically Referenced Counterbalance Valve
• Cavity: T-11A
• Capacity: 30 L/min / 7.5 GPM
• Pilot Ratio: 4.5:1
• Control: Standard Screw Adjustment
• Functional Setting Range: 70–280 bar
• Standard Setting: 210 bar
• Check Cracking Pressure: 1.7 bar
• Maximum Setting: 280 bar
• Maximum Recommended Load Pressure at Maximum Setting: 215 bar
• Adjustment: 3 turns
• Installation Torque: 40–50 Nm
• Approx. Weight: 0.15–0.16 kg
• Seal: Buna-N
• Vent: Atmospherically referenced

CBEH-LKN

• Valve Type: Counterbalance Valve with Pilot Assist
• Cavity: T-2A
• Capacity: 120 L/min / 30 GPM
• Pilot Ratio: 10:1
• Control: Standard Screw Adjustment
• Configuration: Non-vented
• Seal: Buna-N
• Hydraulic Function: Free-flow check toward the load with pilot-assisted relief in the reverse direction
• Pressure Range: Depends on the complete pressure-range suffix

Sun Hydraulics identifies the CBEH family as a T-2A, 120 L/min, 10:1 pilot-ratio counterbalance configuration.

CBEH-LIN

• Manufacturer: Sun Hydraulics family
• Series: CBEH
• Model Code: CBEH-LIN
• Configuration: Counterbalance valve
• Control: Standard Screw Adjustment
• Seal: Buna-N
• Pilot Ratio: 10:1 family
• Cavity: T-2A family
• Exact “I” pressure range: Not independently verified from currently accessible manufacturer documentation

Because the exact I-range was not verified from a sufficiently reliable manufacturer source, no numerical setting range is assigned here.

Displacement, Speed and Peak Pressure

These are cartridge hydraulic valves rather than hydraulic pumps or motors.

• Displacement: Not applicable
• Maximum Speed: Not applicable
• CKCD Maximum Operating Pressure: 350 bar / 5,000 psi
• Peak Pressure: No separate verified CKCD peak-pressure specification was identified in the available manufacturer documentation

Key Technical Advantages

1. Sealed Pilot for Reduced Cross-Port Leakage

The CKCD uses a sealed pilot specifically for hydraulic circuits where cross-port pilot leakage is undesirable.

2. 3:1 Pilot Ratio

A 3:1 pilot ratio provides a defined relationship between load pressure and pilot pressure, allowing engineers to size the pilot circuit according to the actual actuator load and backpressure conditions.

3. Extremely Low Leakage

The CKCD is specified for maximum leakage of:

0.07 cc/min at 24 cSt

This is important for actuator position retention and long-duration load holding.

4. Steel Seat and Robust Check Construction

The valve uses a steel seat, and Sun Hydraulics emphasizes treated sealing surfaces in its check-valve construction for long service life and low leakage.

5. 60 L/min Flow Capacity

The CKCD provides:

60 L/min / 15 GPM

in a compact Series 1 cartridge format using the T-11A cavity.

6. Locking Valve, Not Motion-Control Valve

The key application distinction is:

CKCD = Load locking

CACG / CABG / CBEH = Counterbalance and motion control

Sun Hydraulics explicitly recommends counterbalance valves for motion-control applications involving overrunning loads.

Application Areas

CKCD-XCN / CKCD-LCN

• Hydraulic Cylinder Load Locking
• Vertical Cylinder Holding
• Hydraulic Clamping
• Press Position Holding
• Mobile Hydraulic Equipment
• Lifting Systems
• Hydraulic Manifolds
• Actuator Drift Prevention
• Hose-Break Protection
• Industrial Hydraulic Power Units

CACG / CABG / CBEH

• Overrunning Load Control
• Hydraulic Winches
• Boom Circuits
• Mobile Cranes
• Hoisting Machinery
• Controlled Lowering Systems
• Hydraulic Motors
• Vertical Motion-Control Circuits

Expert Maintenance Tips

1. Verify the T-11A Cavity

CKCD cartridges require:

T-11A cavity

Always confirm the manifold cavity before replacement.

2. Distinguish CKCD-XCN from CKCD-LCN

CKCD-XCN

= Standard Pilot + 2 bar cracking pressure + Buna-N

CKCD-LCN

= Manual Load Release + 2 bar cracking pressure + Buna-N

The control option must be preserved during replacement.

3. Use 41–47 Nm Installation Torque

The published installation torque for the CKCD cartridge is:

41–47 Nm

Use a calibrated torque wrench during installation.

4. Install Close to the Actuator

For load-locking applications, locate the pilot-to-open check valve as close to the actuator as practical to reduce hydraulic compliance and pressure-response delay.

5. Investigate Contamination When Load Drift Occurs

If unexpected actuator movement occurs, inspect:

Seat → Poppet → Contamination → Seal Condition

Sun Hydraulics specifically notes that load drift caused by the valve can indicate contamination-related seat damage.

6. Do Not Treat CACG, CABG, CBEH and CKCD as Equivalent

Even where cartridge cavities or flow sizes are related, their hydraulic functions are different:

CKCD = Pilot-to-Open Check / Load Locking

CACG / CABG / CBEH = Counterbalance / Motion Control

A mechanically compatible cartridge is therefore not automatically a hydraulically equivalent replacement.