I’m on the bubble at work, but my mother in law bought a house because f’me. So I have to cut a client meeting short becuase she calls up like a raving panicked hysterical chicken. An hour later, I show up at her place and find the picture below. House has pool. I’ve never seen anything like this. 3 valves and the overpressure whatever the fck (?).

The one most to the right shuts off the waterfall. But why? Which comes from the city into the house, what goes to the pool, what goes to the house? How would I know? Can someone explain this configuration to me and maybe make a first diagnostic guess as to why this suddenly started?