Massachusetts Wastewater Practice Exam

If a high head pump sounds like it is pumping rocks, what should you do?

1. Restrict discharge

2. Restrict intake

3. Do nothing

4. Increase pumping rate

The correct answer is: Restrict discharge

When a high head pump sounds like it is pumping rocks, this typically indicates that there is an issue with the flow entering the pump or that there might be a blockage or air entrainment. In this scenario, restricting the discharge is the appropriate action to take. Restricting discharge can help to reduce the pressure and allow the pump to operate more safely and effectively. By limiting the flow out of the pump, you can potentially minimize the cavitation that may occur when the pump is trying to move water at an inappropriate rate or when it is experiencing turbulence from inadequate intake flow. This action can help in diagnosing the issue further by observing the changes in pump sound, pressure, and discharge characteristics. Lastly, it ensures the longevity of the pump by preventing excessive strain or possible damage due to operating under adverse conditions. Other options like restricting intake could exacerbate the problem, leading to cavitation, while doing nothing would ignore the warning signs, and increasing the pumping rate could worsen the situation by stressing the pump further.