What issue arises when a pump operates under suction lift?

When a pump operates under suction lift, one of the critical issues that can arise is the introduction of air into the water stream along the shaft. This situation often occurs because, in a suction lift operation, the pump is drawing water up from a lower level. If there are any leaks in the suction line or at the seals of the pump, air can be drawn in alongside the water, leading to a condition known as cavitation. This not only reduces the efficiency of the pump but can also cause significant damage over time due to vapor bubbles collapsing within the pump.

The entry of air compromises the hydraulic performance of the system, leading to inconsistent flow rates and pressures, and can impair the pump's ability to operate efficiently. Proper sealing and maintenance of the suction line are crucial to prevent air from infiltrating the water stream, thus safeguarding the pump's performance and longevity.