What is the Diameter of your Sump Basin?

This is important when choosing a sump pump because there are several switch types available.  The diameter of the sump basin is a very large part in which switch is right for you.
Measure the inside diameter of your sump pit at the narrowest point, down in the area where the pump will operate (shown by the red arrow in the picture here:

In short, the basin must be large enough so that the switch does not rub, or get stuck on, the wall of the basin.  If the float ball can get stuck on the basin side:
    -- It may not be able to float up and turn the pump on.
            This means a flooded basement!
    -- It may not drop down to power off when the water is gone.
            This means a burned -up pump!

If you are installing a new sump pump where there was none before, install a LARGE basin.

WHY?  Because you want your pump to last a long time.

It is better for a sump pump to run a little longer each time it runs, and be off longer between cycles.  This allows the pump to cool more completely, giving the motor a better chance at a long life.


A small sump basin means the pump has to run more often.  Often, this means the pump cannot cool down completely between pump cycles.  Overall, it runs hotter.  An electric motor that runs hotter may mean a shorter life for that motor.

You may also see some small energy savings with a larger sump pit.  An electric motor draws more power to get it started than it does while it's running.  Fewer start-ups can mean less power is used!

Next:  Selecting Your Switch

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