Noise can be a warning
Cavitation forms when local liquid pressure falls to vapour pressure and the vapour cavities collapse in a higher-pressure region. Gravel-like noise, vibration and reduced performance may follow. Not every noise is cavitation: air ingress, bearing damage and mechanical contact can look similar. Diagnosis should combine measurements with inspection.
NPSHa is not NPSHr
NPSHa describes what the system makes available; NPSHr describes the pump requirement at a given flow. Availability must exceed the requirement with the margin specified for the application and manufacturer. There is no universal margin. Higher liquid temperature raises vapour pressure, while clogged strainers and suction losses reduce the available margin.
Inspect the suction side first
Check tank level, inlet pressure, temperature, strainer condition and valve positions first. Inspect air pockets, undersized pipework and elbows too close to the inlet. Reducing speed or flow can help in some cases, but a lasting correction may require measured system changes or reselection. Stay within the manufacturer’s permitted operating range.
Let’s select the right product.
Your contact information and a short description are enough to start. Add flow, head, fluid and quantity if known; we can clarify the rest together.