Every system is unique and requires specific engineering data to correctly size and design. Typically, a valve is replaced with another valve of the same size.
Important: An undersized valve does not deliver the required amount of water
flow under full load conditions, and an oversized valve tends to hammer under low load
conditions.
To select the correct valve size, determine the following variables:
- Maximum water flow required
- Available water pressure drop across the valve, also known as the differential
Use these variables to locate a point on one of the flow capacity charts (from Figure 1 to Figure 4) that slightly exceeds the maximum water flow that you need. The flow capacity chart that contains this point represents the correct valve size.