Where should a backflow preventer be located in a boiler system?

In a boiler system, the backflow preventer plays a crucial role in ensuring that water flows in only one direction, preventing contaminated water from flowing back into the potable water supply. The most appropriate location for a backflow preventer is at the water supply entry. This placement serves as the first line of defense against potential backflow, safeguarding the overall water quality.

Positioning the backflow preventer at the water supply entry ensures it can effectively block any backflow that could occur due to pressure changes within the system. Options that mention placing the backflow preventer on specific lines or near auxiliary components, such as the expansion tank or pump discharge, do not serve this primary function as effectively. While these locations may have their own importance in the system, they do not address the critical need for protecting the potable water source from contamination caused by backflow. Thus, the correct placement of the backflow preventer contributes significantly to maintaining the integrity and safety of the water supply.