Four points should be noted when starting a centrifugal pump:

① The head generated by a centrifugal pump at a certain speed has a limited value. The flow rate and shaft power at the working point depend on the condition of the device system connected to the pump (such as position difference, excitation difference, and pipeline loss). The head changes with the flow rate.

② Stable operation, delivering continuous flow and pressure without pulsation.

③ Generally, there is no self-priming ability, and the pump needs to be filled with liquid or the pipeline needs to be evacuated before it can start working.

④ The centrifugal pump starts when the discharge pipeline valve is closed, while the vortex pump and axial flow pump start when the valve is fully open to reduce the starting power.

Because centrifugal pumps rely on the centrifugal force of the impeller to create vacuum suction and lift water, when starting the centrifugal pump, the gate valve must be closed first and water must be filled. When the water level exceeds the impeller, the air in the centrifugal pump must be discharged before starting. After starting, a vacuum is formed around the impeller, which draws water upwards. Its gate valve can automatically open to lift the water. Therefore, the gate valve must be closed first.