The sanitary expansion vessel in storage boilers is essential when there is a significant storage capacity. As the water in the tank heats up, it expands in volume. This component reduces the load on the safety valve of the sanitary system.
Usually placed under the boiler, it is a faucet that bridges between the water main and the heating circuit. It is used to charge the system to a pressure of 1.2 bar / 1.5 bar.