What can happen if priming is not maintained during pumping operations?

• A. It has no effect on pump performance.
• B. When the pump loses prime, the air escapes through the discharge valve.
• C. It increases discharge flow automatically.
• D. It can cause cavitation and loss of prime.

Answer: (D)

Priming keeps the pump full of water on the suction side, creating a seal so the pump can draw water effectively. If priming isn’t maintained, air gets pulled into the pump, the prime is lost, and the suction pressure can drop below the water’s vapor pressure. That causes cavitation—tiny vapor bubbles form and then collapse inside the impeller—leading to noise, vibration, reduced flow, and potential damage. Until prime is reestablished, the pump won’t deliver water properly.