Before changing from tank water to an external source, what should an operator ensure?

Before transitioning from tank water to an external source, it is essential for the operator to ensure that all air is bled from the intake line. When operating a pump, air in the intake lines can lead to cavitation, which can severely damage the pump and impair its ability to function effectively. By bleeding any air from the intake, the operator ensures that a clear and steady supply of water is being drawn from the external source. This process helps maintain proper pump operation and efficiency, allowing for optimal water flow and pressure.

The importance of this action can't be overstated; it safeguards the equipment and enhances operational reliability during critical fire fighting scenarios. While ensuring water lines are filled, ensuring the pump is at maximum capacity, or ensuring the tank is empty may be useful considerations in certain contexts, these factors do not address the root concern of preventing air from interfering with the incoming water supply.