What is the maximum percentage decrease in impeller diameter that can be made without adverse effects?

The maximum percentage decrease in impeller diameter that can be made without adverse effects is typically considered to be around 20 percent. This limit is based on the impact that changes in impeller diameter can have on the pump's performance characteristics.

When the diameter of the impeller is reduced, the pump's flow rate, head, and efficiency are affected. A decrease of up to 20 percent usually maintains the operational integrity and ensures that the pump can still perform effectively within its designed application.

Exceeding this threshold may lead to significant drops in performance, reasons for cavitation, increased vibration, or even mechanical failure over time. Therefore, understanding the implications of impeller diameter adjustments is crucial for maintaining system reliability and functionality in plumbing designs and applications.