Why does a geyser need an anti-syphon loop?

Hello There!
This is the first video in the Series on Notes to Installing an Apollo Solar Geyser.
Today we will be looking at the Integrated High-Pressure System, specifically the anti-syphon loop part of the installation and how a vacuum Breaker works.

Видео Why does a geyser need an anti-syphon loop? канала Apollo Solar Technology