How would you correct a jet pump two-pipe system that is sucking air?

In a jet pump two-pipe system that is sucking air, the problem often relates to improper sizing of the suction and drive lines, which can lead to insufficient pressure and allow air to enter the system. By decreasing the sizes of these lines, you can increase the velocity of the water flow, enhancing the pump's ability to maintain a consistent prime and thereby reducing or eliminating the risk of air being drawn into the system.

Reducing the line size can help create a more consistent flow rate, which is crucial for the jet pump's operation. If the lines are too large, it can allow for turbulence and decreased pressure, making the system more prone to drawing in air. This adjustment helps ensure that the system remains fully primed and operates effectively.

In contrast, simply increasing pump pressure, replacing the impeller, or cleaning the inlet strainer might not address the underlying issue of air ingress due to line sizing. Thus, modifying the diameter of the suction and drive lines is a more effective solution for maintaining reliable pump operation and preventing air from entering the system.