Tennessee Wastewater Operator Practice Exam

Which mechanical problem is most likely to cause a lift pump to fail?

1. Capacity overflow

2. Shaft binding or sticking

3. Pump size mismatch

4. Improper voltage supply

The correct answer is: Shaft binding or sticking

Shaft binding or sticking is the most likely mechanical problem to cause a lift pump to fail because it directly impedes the pump’s ability to operate effectively. A pump's shaft must rotate freely to generate the necessary pressure and flow rate to move wastewater. If the shaft becomes bound or sticks due to misalignment, wear, or debris accumulation, the motor may become overloaded, leading to overheating and eventual failure of