In a two-pump wet well where lag pump is clogged, what is the most likely cause of a problem where the wet well level stays excessively high despite the lead pump running?

In a two-pump wet well where lag pump is clogged, what is the most likely cause of a problem where the wet well level stays excessively high despite the lead pump running?

• A. Lag pump clogged
• B. Lead pump overload
• C. Electrical fault in lag pump
• D. Discharge line blockage

Answer: (A)

In a two-pump wet well, the lead pump handles normal flow and the lag pump provides extra capacity when the level rises. If the lag pump is clogged, it can’t move water at all when the level starts to increase. Even though the lead pump is running, there’s now only one pump’s pumping capacity available, which may be insufficient to keep the wet well from rising under higher inflow. That’s why the water level stays excessively high. If the lead pump were truly overloaded or there were an electrical fault in the lag pump, you’d expect symptoms like the lead pump slowing, tripping, or the lag pump not starting at all, rather than the specific clue of a clogged lag pump preventing backup capacity. A discharge line blockage could also raise level, but the question’s scenario points to the lag pump being unable to contribute due to clogging, directly causing the persistent high level.

In a two-pump wet well, the lead pump handles normal flow and the lag pump provides extra capacity when the level rises. If the lag pump is clogged, it can’t move water at all when the level starts to increase. Even though the lead pump is running, there’s now only one pump’s pumping capacity available, which may be insufficient to keep the wet well from rising under higher inflow. That’s why the water level stays excessively high.

If the lead pump were truly overloaded or there were an electrical fault in the lag pump, you’d expect symptoms like the lead pump slowing, tripping, or the lag pump not starting at all, rather than the specific clue of a clogged lag pump preventing backup capacity. A discharge line blockage could also raise level, but the question’s scenario points to the lag pump being unable to contribute due to clogging, directly causing the persistent high level.