CBCA-LHN SUN 3:1 Counterbalance Valve Cartridge 15gpm

Product Overview

The CBCA-LHN is a SUN Hydraulics 3:1 pilot ratio, standard capacity counterbalance valve (also known as a motion control or overcenter valve). It incorporates a check valve that allows free flow from the directional valve (port 2) to the load (port 1), while a direct-acting, pilot-assisted relief valve controls flow from port 1 to port 2. Pilot pressure at port 3 reduces the effective relief setting at a 3:1 ratio, providing precise control of overrunning loads and reliable load holding. Built with SUN’s floating construction and exact T-11A cavity compatibility, the valve offers 100% drop-in interchangeability and is validated through simulated operating condition testing for consistent high-pressure performance.

Technical Specifications 

• Model: CBCA-LHN
• Type: 3:1 pilot ratio, standard capacity counterbalance valve
• Capacity: 15 gpm (60 L/min)
• Cavity: T-11A (Series 1)
• Pilot Ratio: 3:1
• Maximum Recommended Load Pressure at Maximum Setting: 3075 psi
• Maximum Setting: 4000 psi
• Functional Setting Range (H): 1000–4000 psi with 25 psi check, 3000 psi (210 bar) standard setting
• Control: L (Standard Screw Adjustment)
• Seal Material: N (Buna-N)
• Factory Pressure Settings Established at: 2 in³/min
• Maximum Valve Leakage at Reseat: 5 drops/min
• Adjustment: Approximately 3.75 counterclockwise turns from minimum to maximum setting
• Operating Characteristic: Standard
• Reseat: >85% of setting
• Valve Hex Size: 7/8 in.
• Installation Torque: 30–35 lbf·ft
• Adjustment Screw Internal Hex Size: 5/32 in.
• Locknut Hex Size: 9/16 in.
• Locknut Torque: 80–90 lbf·in
• Weight: Approx. 0.35–0.44 lb
• Seal Kits: Buna 990011007 and others available

Key Technical Advantages

• 3:1 pilot ratio provides sensitive pilot opening while maintaining secure load holding, effectively controlling overrunning loads and reducing system shock.
• High reseat ratio (>85% of setting) and very low leakage (5 drops/min at reseat) ensure reliable load locking and prevent gradual settling.
• SUN floating construction compensates for cavity tolerances and installation torque variations, minimizing internal binding and ensuring long-term interchangeability.
• Integrated check and pilot-assisted relief functions simplify circuit design; the cartridge can be installed directly into an actuator housing for improved stiffness and protection.
• Precision machining, robust materials, and 100% simulated-duty testing guarantee stable performance and extended service life under maximum setting pressure and repeated load cycles.

Application Areas

Ideal for load holding and overrunning load control in hydraulic systems, including crane and aerial work platform lift cylinders, excavator and loader boom/arm control, forklift and stacker fork lift circuits, agricultural and forestry machinery lift mechanisms, injection molding and press safety load control, and any mobile or industrial equipment requiring overcenter control to prevent uncontrolled load descent.

Expert Maintenance Tips

Ensure the T-11A cavity is clean and free of burrs before installation. Tighten to the specified 30–35 lbf·ft torque. Set the counterbalance valve at least 1.3 times the maximum load-induced pressure. Turn the adjustment clockwise to decrease setting and release the load; full clockwise setting is less than 200 psi. Note that backpressure at port 2 adds to the effective relief setting at a ratio of (1 + pilot ratio). Maintain fluid cleanliness at ISO 4406 18/15 or better and periodically check leakage and reseat performance. Use only recommended seal kits. After initial installation, verify the set pressure and load-holding function.