The static pressure of a system is the pressure that is not provided by the circulator pump. In open systems, the static pressure depends on the geodetic height of the system.
There are two types of systems: open systems and pressurised systems.
In open systems, the static pressure is defined as the difference in static pressure between the highest-placed open water level and the water outlet level.
A pressurised system typically has a pressure expansion tank, often with a rubber membrane, which separates the compressed gas and the water in the system.
The static pressure has a significant influence on pumps and valves. If the static pressure is too low, the risk of cavitation increases, especially at high temperatures.