I have a 1971 31' Airstream Land Yacht.
It is in the process of being remodeled and we came upon these plumbing components in the rear bathroom area.
I know the white thing on the left is the 'T valve' for the sewage system.
What are the knob valves and that pressure regulator? to the right.
Trying to identify what these pipes and valves are for.
ALSO: why so many electrical wires going to that one box with only a red light?
Many thanks!!!
pic here:
https://imgur.com/a/6OTkGa4