In a two-pipe direct return hot water heating system, how is water supplied to heating units?

In a two-pipe direct return hot water heating system, all heating units are supplied with water at the same temperature. This system is designed to maintain consistency in the water temperature provided to each unit, ensuring efficient heating throughout the space.

In a direct return configuration, hot water is delivered from a central boiler through one pipe to the heating units, and a return pipe brings the cooled water back to the boiler. Since all units draw from the same source, they receive water that has been uniformly heated, which promotes even temperature distribution and effective heating performance across the system.

This method is preferable because it simplifies the control and management of the heating system, improving overall efficiency. It avoids complications that might arise from varying temperatures, which can lead to uneven heating and discomfort in different areas. Consequently, option B reflects the core principle of uniform water supply in such a system.