CAEG-LGN Sun Hydraulics Counterbalance Valve 420 Bar

Product Overview

The Sun Hydraulics CAEG-LGN is an atmospherically vented counterbalance valve designed for hydraulic load holding, overrunning-load control and controlled actuator movement.

The CAEG-LGN uses the T-2A cavity, provides 120 L/min nominal capacity, and has a maximum setting of 420 bar. Its documented configuration uses a 5:1 pilot ratio, standard screw adjustment, a 1.7 bar check cracking pressure and Buna-N sealing. The published technical data also specifies a maximum recommended load pressure of 320 bar at the maximum setting.

A counterbalance valve should not be treated as a conventional pressure-relief valve. Its main function is to control overrunning loads, maintain actuator position and provide controlled release when pilot pressure is applied.

The additional models in the original title represent different hydraulic functions:

• PVDB-LWN — 3-way pilot-operated ventable pressure reducing/relieving valve, T-21A, 40 L/min.
• XCOA-XXN — cavity plug for T-3A, T-5A and T-32A cavities. It is a manifold accessory rather than an active control valve.

For replacement applications, the correct engineering selection sequence is:

Function → Cavity → Pilot Ratio → Pressure Range → Check Configuration → Seal → Complete Model Code

Technical Specifications

CAEG-LGN

• Model: CAEG-LGN
• Brand: Sun Hydraulics
• Valve Type: Atmospherically vented counterbalance valve
• Cavity: T-2A
• Nominal Capacity: 120 L/min (30 GPM)
• Pilot Ratio: 5:1
• Maximum Setting: 420 bar (6000 psi)
• Maximum Recommended Load Pressure at Maximum Setting: 320 bar (4615 psi)
• Pressure Range: 140–420 bar for the G configuration
• Standard Setting: 280 bar (4000 psi)
• Adjustment: L — Standard Screw
• Adjustment Range: 5 turns
• Check Cracking Pressure: 1.7 bar (25 psi)
• Factory Setting Flow: 30 cc/min
• Maximum Reseat Leakage: 0.3 cc/min
• Seal: N — Buna-N
• Alternative Seal: Viton available within the family
• Valve Hex: 28.6 mm / 1-1/8 in
• Installation Torque: 60–70 Nm
• Adjustment Screw Internal Hex: 4 mm
• Locknut/Cap Hex: 15 mm
• Adjustment Nut Torque: 9–10 Nm
• Reference Weight: approximately 0.38 kg
• Function: Load holding and pilot-assisted control of overrunning loads
• Venting: Atmospherically referenced.

PVDB-LWN

• Model: PVDB-LWN
• Brand: Sun Hydraulics
• Valve Type: 3-way, pilot-operated, ventable pressure reducing/relieving valve
• Cavity: T-21A
• Nominal Capacity: 40 L/min (10 GPM)
• Control: Pilot operated
• Vent: Ventable
• Adjustment: L — Standard Screw
• Function: Pressure reduction and relieving
• Published Family Setting Data: approximately 10.5–315 bar depending on configuration
• Exact Maximum Rating: Must be confirmed against the complete model code and primary technical documentation before being used as a certified model-specific value
• Displacement: Not applicable
• Rated Speed: Not applicable.

XCOA-XXN

• Model: XCOA-XXN
• Brand: Sun Hydraulics
• Product Type: Cavity plug
• Function: Cavity closure / manifold configuration
• Compatible Cavities: T-3A, T-5A and T-32A
• Interface: All ports open in the documented configuration
• Seal: N configuration / Buna-N
• Reference Weight: approx. 0.11 kg
• Flow Rating: Not applicable as an active valve
• Displacement: Not applicable
• Rated Speed: Not applicable.

Key Technical Advantages

5:1 Pilot Ratio

The 5:1 pilot ratio allows relatively low pilot pressure to control a significantly higher load-side pressure, making CAEG-LGN suitable for hydraulic cylinders, winches and other overrunning-load applications.

420 Bar Maximum Setting

The CAEG-LGN supports a 420 bar maximum setting, placing it in a high-pressure class. However, the documented maximum recommended load pressure at maximum setting is 320 bar, which must be distinguished from the valve setting itself.

120 L/min Capacity

With 120 L/min nominal capacity, CAEG-LGN can serve medium- and high-flow actuator circuits, including lifting, winch and mobile-hydraulic applications.

Atmospheric Venting

The valve is atmospherically referenced, differentiating it from counterbalance architectures that rely on an externally pressurized vent connection.

Five-Turn Adjustment

The L control provides approximately five turns of adjustment, allowing engineers to fine-tune load holding and controlled-lowering behavior.

Integrated Check Function

The counterbalance architecture provides free flow in the charging direction while controlling reverse flow through the pilot-assisted load-control stage.

T-2A Cartridge Integration

The T-2A cavity supports compact manifold-based hydraulic system architecture and simplifies integration into cartridge-valve blocks.

Modular Replacement Architecture

Sun’s cartridge architecture supports service and replacement strategies based on cavity and function. Cavity compatibility, however, must be combined with pilot ratio, pressure range, seal configuration and hydraulic function verification.

Application Areas

CAEG-LGN

• Hydraulic cylinders
• Boom and arm circuits
• Hydraulic winches
• Hoists
• Lifting platforms
• Material-handling equipment
• Construction machinery
• Mobile cranes
• Overrunning-load circuits
• Controlled-lowering systems
• Load-holding applications

The typical hydraulic operating sequence is:

Load Holding → Pilot Command → Controlled Opening → Smooth Load Release

PVDB-LWN

• Secondary pressure-control systems
• Pilot-operated reducing circuits
• Hydraulic power units
• Industrial manifolds
• Pressure-reduction systems
• Pressure-limiting and relieving applications

PVDB-LWN should be selected as a pressure reducing/relieving valve, not as a substitute for a counterbalance valve.

XCOA-XXN

• Hydraulic manifold cavity closure
• Unused cavity sealing
• Valve-block reconfiguration
• Maintenance applications
• Cavity plugging

XCOA-XXN is a cavity plug and should not be marketed as an active hydraulic control valve.

Expert Maintenance Tips

Calculate Load-Induced Pressure First

Counterbalance settings should be derived from actual load-induced pressure rather than simply selecting the system’s highest pressure rating.

For CAEG-LGN, the published maximum recommended load pressure at the maximum setting is 320 bar.

Analyze Pilot Ratio During Instability

A 5:1 ratio may provide strong pilot assistance, but circuit stability depends on:

Pilot Ratio + Flow + Load Pressure + Setting + Pilot-Line Restriction

Chatter, oscillation and jerky lowering should therefore be analyzed as a complete hydraulic-system problem.

Adjust Under Representative Flow

Counterbalance behavior changes with load and flow. Pressure settings should be verified under operating conditions representative of the actual machine rather than only at near-zero flow.

Apply 60–70 Nm Installation Torque

The documented CAEG-LGN T-2A installation torque is 60–70 Nm. Excessive torque can influence cartridge-body stress, sealing and internal mechanical movement.

Inspect the Check Section

Slow actuator filling, excessive pressure drop or unexpected reverse-flow restriction can indicate contamination or wear in the integrated check section.

Verify the Seal Material

N specifies Buna-N for the documented configuration. Viton versions should only be selected when the complete ordering code and hydraulic-fluid requirements support them.

Verify PVDB Vent Routing

For PVDB-LWN, the ventable reducing/relieving architecture requires correct pilot and vent/tank routing. The valve should not be treated as an ordinary two-port pressure regulator.

Confirm the XCOA Cavity

XCOA-XXN is compatible with T-3A, T-5A and T-32A cavity applications. Verify the actual manifold cavity before installation.

Perform Dynamic Load Testing

For CAEG-LGN replacement units, test:

Load → Counterbalance Setting → Pilot Pressure → Controlled Opening → Reseat

Measure:

• Setting pressure
• Pilot pressure
• Opening response
• Controlled-lowering stability
• Pressure override
• Internal leakage
• Reseat performance
• Repeated-cycle stability

Use 100% Simulated Working-Condition Testing

A representative replacement test bench can reproduce:

Hydraulic Power Unit → CAEG-LGN → Cylinder/Motor Load Simulator → Pilot Circuit

Test static load holding, full load, partial load, controlled lowering, sudden load changes, pilot-pressure variation and repeated pressure cycles.

This gives a stronger engineering basis for in-place interchangeability and 100% simulated working-condition testing than dimensional inspection alone.