What component allows a multistage pump to switch between series and parallel operation?

The component that allows a multistage pump to switch between series and parallel operation is the transfer valve. This valve is specifically designed to manage the flow paths within the pump system.

In series operation, the pumps are configured to function one after another, which increases the pressure of the fluid being pumped. This setup is beneficial when a high discharge pressure is required. On the other hand, in parallel operation, pumps work simultaneously to increase the flow rate while maintaining the same pressure, which is ideal for handling larger volumes of fluid.

The transfer valve facilitates the transition between these two configurations by directing the flow of liquid through the appropriate pathways, allowing operators to adjust the pump's operation based on the specific demands of the situation. This versatility is critical for firefighting and other applications where flow and pressure requirements can change rapidly.