Cavitation decreases a water pump’s output due to the combination of liquid and vapor in the pump’s inlet chamber. Cavitation will not only cause pitting in the valves and manifold, but also reduces the lubrication of the seals, resulting in reduced seal life. Eventually, cavitation leads to loss of pump flow and therefore lack of system pressure to do the job. Cavitation also produces excessive pump noise.
Cavitation occurs when there isn’t a sufficient volume of water at the water pump inlet. When this happens, some of the water vaporizes to fill the low-pressure chamber of the pump. On the forward stroke of the pump, vapor “bubbles” are pressurized, quickly collapsing and causing violent implosions. The release of energy created by these implosions causes pitting and erosion of the water pump’s internal parts.
Best practices to prevent water pump cavitation include:
- Increase the size of the pump inlet line – it should be one size larger than the pump inlet port.
- Use flexible reinforced hose at the pump inlet and discharge the pump ports to absorb pulsation and pressure spikes.
- Keep elbows on the pump inlet line to a minimum and less than 90° if possible.
- Check all connections and plumbing on the pump’s inlet for air leaks.
- Clean inlet filters or strainers regularly.