Newly installed sump pump sitting in a basement sump pit

Field pattern: new sump pump runs but the pit stays full (air lock, check valve and discharge before a second pump)

When a pump runs but moves little water, the cause is often outside the motor: an air-locked volute (missing or plugged weep hole), a check valve installed backward or stuck, a closed or frozen discharge, a clogged inlet screen, or too much lift for the pump. The wrong turn is buying a second pump.

Cross-checked ~60 min moderateBrands: Zoeller, Wayne, Liberty, Pentair, All

Before you start

Unplug the pump before reaching into the pit; sump outlets should be GFCI protected
Wear gloves; pit water can contain sewage or chemicals
Sewage ejector basins are sealed and vented; opening them is a plumber's job

Diagnostic steps

Unlock all 6 steps with expected values

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