Question: What can be the reason for noisy booster system?

Do you have issues with noise in your booster system? In most cases, noisy pipes indicate problems in the water supply system. Since noise is easily transmitted via structures and components in the water supply system, it can be difficult to identify the source of the issue. However, the most common reason is due to poor pump technology or poor pump control. Systems with older centrifugal pumps that use fan-cooled motors, for instance, can generate vibrations throughout the system, resulting in more noise. Inefficient pumps that run constantly, even when there is no water being used, or poorly installed booster pumps that are not secured to the floor, can cause vibrations and noise in the system. SCALA2 a low noise pressure booster solution omitting < 47 dB(A), which is the same as a silent dishwasher. See more https://www.grundfos.com/solutions/learn/research-and-insights/lack-of-water-pressure-or-noisy-boosting-system