CWCG-LGN CWGG-LGN CKIB-XCN Sun Hydraulic Cartridge Valve 350 bar

Product Overview

This SUN series screw-in cartridge valve portfolio covers three core models: CWCG-LGN, CWGG-LGN, and CKIB-XCN. These products span two major functional categories — load holding (counterbalance) and directional control (pilot-to-open check) — delivering comprehensive cartridge valve solutions for hydraulic systems.

• CWCG-LGN: 5:1 pilot ratio, vented counterbalance valve with 60 L/min capacity for smooth control of overrunning loads and load-holding.

• CWGG-LGN: 5:1 pilot ratio, vented counterbalance valve with 240 L/min capacity for high-flow overrunning load control applications.

• CKIB-XCN: 3:1 pilot ratio, pilot-to-open check valve with 480 L/min capacity for zero-leakage load locking and hose break protection.

All models feature screw-in cartridge construction for direct installation into standardized SUN cavities, offering convenient assembly and low maintenance costs.

As a high-performance alternative to genuine Sun Hydraulics series products, this portfolio delivers full performance parity with Sun original specifications, featuring 100% form-fit-function interchangeability — cavity dimensions, installation torque specifications, and performance parameters are identical to the original, enabling direct replacement without manifold modifications. Every unit undergoes 100% simulated in-service testing prior to shipment, ensuring proven reliability under real-world operating conditions.

Technical Specifications 

CWCG-LGN — 5:1 Pilot Ratio, Vented Counterbalance Valve

• Product Type: 5:1 pilot ratio, vented counterbalance valve (4-port with vent)

• Cavity: T-21A

• Series: 1

• Capacity: 15 gpm (60 L/min)

• Maximum Operating Pressure: 5000 psi (350 bar)

• Maximum Setting: 6000 psi (420 bar)

• Minimum Setting: 140 bar

• Pilot Ratio: 5:1

• Maximum Recommended Load Pressure at Maximum Setting: 4615 psi (320 bar)

• Check Cracking Pressure: 40 psi (2.8 bar)

• Reseat: >85% of setting

• Maximum Valve Leakage at Reseat: 5 drops/min (0.3 cc/min)

• Factory Pressure Settings Established at: 2 in³/min (30 cc/min)

• Adjustment Turns (CCW to Increase Setting): 5

• Valve Hex Size: 7/8 in (22.2 mm)

• Valve Installation Torque: 30 – 35 lbf·ft (41 – 47 N·m)

• Adjustment Screw Internal Hex Size: 5/32 in (4 mm)

• Locknut Hex Size: 9/16 in (15 mm)

• Locknut Torque: 80 – 90 lbf·in (9 – 10 N·m)

• Weight: 0.45 lb (0.20 kg)

• Seal Material: NBR (standard) / Viton (FKM, optional)

• Temperature Range: -30℃ to +110℃

• Recommended Fluid Cleanliness: ISO 4406 Class 19/17/14

• Seal Kits: Viton (990021006)

CWGG-LGN — 5:1 Pilot Ratio, Vented Counterbalance Valve (High Flow)

• Product Type: 5:1 pilot ratio, vented counterbalance valve (4-port with vent)

• Cavity: T-23A

• Series: 3

• Capacity: 60 gpm (240 L/min)

• Maximum Operating Pressure: 5000 psi (350 bar)

• Maximum Setting: 6000 psi (420 bar)

• Pilot Ratio: 5:1

• Maximum Recommended Load Pressure at Maximum Setting: 4615 psi (320 bar)

• Check Cracking Pressure: 25 psi (1.7 bar)

• Reseat: >85% of setting

• Maximum Valve Leakage at Reseat: 5 drops/min (0.3 cc/min)

• Factory Pressure Settings Established at: 2 in³/min (30 cc/min)

• Adjustment Turns (CCW to Increase Setting): 5

• Valve Hex Size: 1 1/4 in (31.8 mm)

• Valve Installation Torque: 150 – 160 lbf·ft (203 – 217 N·m)

• Adjustment Screw Internal Hex Size: 5/32 in (4 mm)

• Locknut Hex Size: 9/16 in (15 mm)

• Locknut Torque: 80 – 90 lbf·in (9 – 10 N·m)

• Weight: 1.59 lb (0.72 kg)

• Seal Kits: Buna (990023007) / Polyurethane (990023002) / Viton (990023006)

CKIB-XCN — Pilot-to-Open Check Valve

• Product Type: Pilot-to-open check valve (non-sealed pilot, steel seat, non-vented)

• Cavity: T-19A

• Series: 4

• Capacity: 120 gpm (480 L/min)

• Maximum Operating Pressure: 5000 psi (350 bar)

• Pilot Ratio: 3:1

• Maximum Leakage at 110 SUS (24 cSt): 1 drop/min (0.07 cc/min)

• Valve Hex Size: 1 5/8 in (41.3 mm)

• Valve Installation Torque: 350 – 375 lbf·ft (474 – 508 N·m)

• Weight: 2.80 lb (1.30 kg)

• Seat Material: Steel (heat treated for long life)

• Pilot Type: Non-sealed pilot (allows air trapped in pilot line to be purged)

• Seal Kits: Buna (990019007) / EPDM (990019014) / Polyurethane (990019002) / Viton (990019006)

Key Technical Advantages

1. Sun Floating-Style Construction — Low Sensitivity to Installation Torque

The most distinctive technical advantage of Sun cartridge valves is the floating-style construction — the working assembly floats within the valve body, significantly reducing sensitivity to installation torque and preventing internal binding caused by excessive torque or cavity machining variations. This design dramatically improves field installation success rates and long-term operational reliability.

2. Standardized Cavity Design — 100% Interchangeability

• CWCG-LGN (T-21A)

• CWGG-LGN (T-23A)

• CKIB-XCN (T-19A)

All models utilize Sun-standard threaded cartridge cavities and are fully interchangeable with genuine Sun products, enabling seamless replacement without manifold modifications — substantially reducing system retrofit and maintenance costs.

3. Vented Design in Counterbalance Valves — Backpressure Does Not Add to Setting

CWCG-LGN and CWGG-LGN feature a vented design — the spring chamber references the vent (port 4), so backpressure at port 2 does not affect the valve setting. This characteristic is particularly valuable in complex hydraulic circuits with significant backpressure, ensuring precise and reliable load control.

4. Ultra-Low Leakage and Long-Life Design

• CWCG-LGN / CWGG-LGN: Reseat leakage of only 0.3 cc/min; reseat pressure exceeds 85% of set pressure

• CKIB-XCN: Leakage as low as 0.07 cc/min; seat and poppet are heat treated for long service life

• CKIB-XCN also provides hose break protection, prevents load drifting, and positively locks pressurized loads

5. Broad Flow Coverage

The portfolio covers an exceptionally wide flow range — from 60 L/min (CWCG-LGN counterbalance) to 480 L/min (CKIB-XCN pilot-to-open check) , with a unified maximum operating pressure of 350 bar. Whether for medium-flow overrunning load control or high-flow load locking applications, a suitable model is available.

Application Areas

CWCG-LGN / CWGG-LGN — 5:1 Pilot Ratio Vented Counterbalance Valves

• Smooth controlled lowering of overrunning loads (booms, arms, etc.)

• Cylinder position holding and load-holding

• Load control for cranes, lifts, presses, and similar equipment

• Direct installation into actuator housing cavities for added circuit protection and improved stiffness

CKIB-XCN — Pilot-to-Open Check Valve

• Cylinder position holding and load locking

• Load drop protection against hose burst failure

• Zero-leakage actuator positioning applications

• Position holding for clamping cylinders in injection molding and die-casting machines

Target Equipment: Injection molding machines, die-casting machines, construction equipment (excavators, loaders), lifting equipment, scissor lifts, mining machinery, machine tool hydraulic systems, and more.

Expert Maintenance Tips

1. Precise Installation Torque Control

Although Sun cartridge valves feature floating-style construction to reduce torque sensitivity, installation torque specifications must still be strictly followed:

• CWCG-LGN (T-21A): 30 – 35 lbf·ft (41 – 47 N·m)

• CWGG-LGN (T-23A): 150 – 160 lbf·ft (203 – 217 N·m)

• CKIB-XCN (T-19A): 350 – 375 lbf·ft (474 – 508 N·m)

Ensure threads are centered during installation and use a torque wrench for proper tightening.

2. Cavity and Mounting Surface Cleaning

Thoroughly clean the cavity interior and mounting surface prior to installation to remove chips, burrs, and contaminants. The shoulder stop at the bottom of the cavity supports the floating portion of the valve — ensure it is free from damage.

3. Seal Selection and Replacement

• Standard mineral oil systems: Buna-N (NBR) seals

• Phosphate ester fluid systems: EPDM seals are mandatory

• High-temperature applications: Viton (FKM) seals

• Replace all cartridge seals after every disassembly

4. Counterbalance Valve Setting and Adjustment (CWCG/CWGG Series)

• Counterbalance valve setting should be at least 1.3 times the maximum load induced pressure

• Turn adjustment clockwise to decrease setting and release load

• Full clockwise setting is less than 200 psi (14 bar)

• Vented design ensures port 2 backpressure does not affect setting — the spring chamber references the vent (port 4)

• Pressure at port 4 is added to the effective relief setting at a rate of 1 plus the pilot ratio times the pressure

5. Fluid Cleanliness Management

• CWCG-LGN / CWGG-LGN: Maintain system fluid cleanliness at ISO 4406 Class 19/17/14 or higher

• CKIB-XCN: If load drifts due to the valve, the seat has probably been damaged by contamination — replace the cartridge

• Installation of a ≤10μm return line filter is recommended for long-term reliability

6. Periodic Functional Testing

• CWCG-LGN / CWGG-LGN: Periodically verify smooth load lowering and check for abnormal vibration, shock, or actuator creep

• CKIB-XCN: Regularly verify load-holding reliability — check for cylinder drift or actuator creep