According to regulations, what size must the manifold and common source connection to the boiler be when multiple process controls are used?

The regulation specifying that the manifold and common source connection to the boiler must be 3/4 inch in size when multiple process controls are used is rooted in the need for adequate flow and pressure to ensure that all controls function effectively. A 3/4 inch diameter allows for sufficient capacity to handle the demands of multiple control systems without causing flow restrictions or pressure drops, which can adversely affect operational efficiency.

Using a diameter smaller than 3/4 inch could lead to insufficient flow rates, leading to unstable operation and potential malfunctions of the controls. Conversely, a diameter larger than 3/4 inch might be unnecessary for the application and could increase costs and installation complexity without providing any operational benefits.