What is a non-return used for in boiler systems?

In boiler systems, a non-return valve, also known as a check valve, is primarily used to regulate the flow of water within the piping to ensure that it moves in one direction only. This function is crucial when two or more boilers are connected to a common header. When multiple boilers are operating, the non-return valve prevents the backflow of water from one boiler into another, ensuring that each boiler operates effectively without interference from the others.

This function is essential for the stability of the system, as backflow can lead to inefficiencies, potential damage, or unsafe operating conditions. The non-return valve secures the integrity of the flow direction, allows for smooth operation, and helps maintain consistent pressure levels across the system when multiple sources are involved.

In contrast, the other options do not fully capture the primary purpose of a non-return valve in this context. They may refer to various functionalities or benefits associated with boiler systems, but they do not accurately describe the specific role of a non-return valve in preventing backflow between connected boilers. Therefore, the focus on the non-return valve's role in a multi-boiler system effectively addresses its critical importance in maintaining system performance and safety.