What should be done first when creating a constant pressure relay?

When creating a constant pressure relay, the initial action taken is critical for establishing an effective water supply system. Positioning the largest capacity apparatus at the water source is the most important first step because this apparatus will have the ability to draw the maximum volume of water available. By ensuring that the largest pump is at the source, it can efficiently supply water to the subsequent apparatus in the relay, maintaining the necessary pressure across the system.

This strategy helps prevent potential issues such as low flow or inadequate pressure, which can occur if smaller or less capable units are placed at the water source. Once the larger unit is engaged and connected, then other apparatus can be deployed and coordinated to ensure a steady and reliable water supply to the firefighting efforts. This methodical approach lays the groundwork for a successful relay operation and aids in maximizing efficiency when responding to the incident.