Hydrostatic and pumping
To maintain constant pressure in the plumbing system
A leak somewhere in the system.
That would depend on which part of the system the RELIEF valve is located
to increase pressure so the water flows and doesent go stale
Depand apone the system required pressure for water supply. it should be 1.5 times of max system pressure and for drainage only gravity pressure is enough to test the system.
50
exspanion tank or relive valve
A vacuum breaker is a mechnical device used to avoid backflow or a negative pressure in a plumbing system. It typically consists of an air valve with a spring holding it closed. When the pressure within the system is positive, the valve remains closed. When the pressure is negative (less than atmospheric), the negative pressure overcomes the force of the spring holding the valve closed and the it opens, typically allowing normal atmospheric air to enter the system, thereby eliminating the negative pressure. Otherwise, the negative pressure might cause backflow of the plumbing system. ...
Yes,the toilet is part of the plumbing system.
I've had that before, and it is generally air in the lines, caused by a clog.
Yes
All pressure is created by gravity. For each meter vertical drop you gain 1 BAR (15lb per square inch) of pressure. Hope that helps :)