The Caleffi safety valve is specially designed for use on boilers. Its main function is to protect the central heating system from excessive pressure. When the pressure exceeds a set level, the valve activates and releases pressure from the system, thereby reducing the risks that may arise for people and materials. It should be installed at the highest point of the setup, without the need for a switch or ball valve.

It is a two-way valve, meaning it has two ports: one for the inlet of the medium and one for the outlet. When the inlet port is closed, the flow is interrupted, while when it is open, the flow at the inlet equals that at the outlet.