Which requirement related to the relief valve for a centrifugal pump is incorrect?

A relief valve for a centrifugal pump is crucial for maintaining system safety and performance by preventing overpressure situations. When considering the requirements for these valves, one key aspect is their sizing and adjustment methods.

The requirement that the relief valve shall only be hydraulically sized is incorrect because relief valves can be appropriately sized using various methods, which may include both hydraulic calculations and other industry-standard sizing practices. It is important that the valve is correctly sized for its application to ensure it operates effectively under the expected conditions, but the sole reliance on hydraulic sizing is not a mandated practice.

In contrast, a relief valve that is manually adjustable allows for fine-tuning to meet specific operational needs, ensuring better adaptability to changing conditions. Having the valve located above the pump is essential as it helps in preventing the accumulation of water that could lead to corrosion or malfunction. Additionally, matching the size of the relief valve to the pump discharge is critical for ensuring that the valve can handle the flow without creating additional pressure issues or risks to the system.