Which of the following can cause a pump to fail to operate?

Air leaks in the suction line can indeed cause a pump to fail to operate effectively. When there is an air leak, the pump is unable to create the necessary vacuum to draw fluid into the suction side. This can lead to cavitation where vapor bubbles form in the fluid because of low pressure, and when these bubbles collapse, they can damage the pump and further reduce its efficiency. The presence of air in the suction line disrupts the continuous flow of liquid, ultimately resulting in pump failure to operate.

Understanding the mechanics of pump operation highlights the importance of maintaining a sealed suction line to ensure reliable performance. In contrast, worn impellers, increased water pressure, and excessive lubrication may contribute to pump issues but do not directly prevent it from operating like air leaks do.