What describes the typical effect of a valve balancing control when demand increases?

• A. Higher flow with lower pressure
• B. Lower flow with higher pressure
• C. No change in flow or pressure
• D. Pressure spikes while flow drops

Answer: (A)

Valve balancing control adjusts the valve position to meet changing demand. When demand increases, the control opens the valve more, allowing more fluid to flow through that branch. At the same time, pushing more flow through the system increases friction losses, so the pressure available at that point tends to decrease. So you end up with higher flow while the pressure is lower. The other options don’t describe the normal response: demand-up typically doesn’t produce no change, nor does it cause a decrease in flow with a pressure rise, and a sudden pressure spike with a drop in flow isn’t the typical steady-state behavior of balancing valves.