Which circuit maintains system pressure when the control valve is in the neutral position?

Which circuit maintains system pressure when the control valve is in the neutral position?

• A. Open-center circuit
• B. Closed-center circuit
• C. Both open-center and closed-center
• D. None of the above

Answer: (B)

The main idea is how the valve arrangement affects pressure when there’s no demand. In a closed-center circuit, the control valve in the neutral (center) position blocks the path from the pump to the actuators, effectively sealing the circuit. With the flow blocked, the pump isn’t sending new fluid, but the fluid that’s already in the lines remains trapped and at the set operating pressure because the system’s relief valve limits the maximum pressure. This lets the hydraulic system hold pressure even when nothing is being actuated, so actuators can stay in place and respond quickly when a command comes. In contrast, an open-center circuit channels the pump output directly back to the tank in neutral. That means the system pressure drops toward zero in neutral because most or all of the pump’s flow is being returned to reservoir rather than building pressure in the lines. So pressure is not maintained in the neutral position. That’s why the closed-center arrangement is the one that maintains system pressure when the control valve is centered.

The main idea is how the valve arrangement affects pressure when there’s no demand. In a closed-center circuit, the control valve in the neutral (center) position blocks the path from the pump to the actuators, effectively sealing the circuit. With the flow blocked, the pump isn’t sending new fluid, but the fluid that’s already in the lines remains trapped and at the set operating pressure because the system’s relief valve limits the maximum pressure. This lets the hydraulic system hold pressure even when nothing is being actuated, so actuators can stay in place and respond quickly when a command comes.

In contrast, an open-center circuit channels the pump output directly back to the tank in neutral. That means the system pressure drops toward zero in neutral because most or all of the pump’s flow is being returned to reservoir rather than building pressure in the lines. So pressure is not maintained in the neutral position.

That’s why the closed-center arrangement is the one that maintains system pressure when the control valve is centered.