expansion vessel

An expansion vessel is a vessel that serves to balance changes in liquid volume caused by temperature changes. It works as an excess pressure regulator in the system. Expansion vessels are commonly used in heating and solar systems and can also function as part of drinking water circuits. Expansion vessels are divided into open and closed.

Open ones are placed at a sufficient height above the pipes, for example on the ground. Today, however, it is an outdated solution. Closed expansion vessels are more modern and are used, for example, in the return pipe or in the pump. This distributes the pressure better in the system.