When is a centrifugal water pump considered to be fully primed?

A centrifugal water pump is considered to be fully primed when the pump is full of liquid. In order for a centrifugal pump to function effectively, it must be completely filled with the fluid it is intended to pump. The reason behind this is that centrifugal pumps operate by creating a difference in pressure to move the liquid; if the pump is not full, air can create a blockage and diminish the efficiency of the pump operation, potentially leading to cavitation or pump failure.

While other aspects, such as having a running motor or a clear suction line, are important for the overall operation and effectiveness of the pump, they do not directly define the priming status of the pump. The maximum pressure is more related to the system's performance rather than the priming state. Therefore, ensuring that the pump is fully filled with liquid is essential for its proper operation and is the key indicator of being fully primed.