CAEA-LHN - Vented Counterbalance Valve, T2-A

Atmospherically-vented counterbalance valves with pilot assist are meant to control an overrunning load. The check valve 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 assist at port 3 lowers the effective setting of the relief valve at a rate determined by the pilot ratio. Backpressure at port 2 does not affect the valve setting because the spring chamber is atmospherically referenced.

Technical Details

• Counterbalance valves should be set at least 1.3 times the maximum load induced pressure.


• Turn adjustment clockwise to decrease setting and release load.


• Full clockwise setting is 0 psi (0 bar).


• Approximately 1 drop of fluid will pass from the pilot area to the vented spring chamber every 4000 cycles.


• Reseat exceeds 85% of set pressure when the valve is standard set. Settings lower than the standard set pressure may result in lower reseat percentages.


• Sun counterbalance cartridges can be installed directly into a cavity machined in an actuator housing for added protection and improved stiffness in the circuit.


• This valve has positive seals between all ports.


• With vented valves, a lower pilot ratio may be required to achieve machine stability compared to non-vented valves.


• Three-port vented valves are atmospherically referenced and considered problem solvers for existing circuits using non-vented valves. Over time, the vented valves may leak externally or allow moisture into the spring chamber. Four-port vented counterbalance valves are recommended


• All 3-port counterbalance, load control, and pilot-to-open check cartridges are physically interchangeable (i.e. same flow path, same cavity for a given frame size).