How does a sump work?

Yes a pool will work without a sump, the sump is good for pulling heated water down to the deeper end so that the pool water is the same temp every where you swim.They dont really act as a cleaner...

1- Unplugged 2- Impeller blocked 3- On thermo over load 4- stoppage down stream 5- check valve hung up 6- pump burned out

Of course as long as the winter never goes below 32 deg F

as well as an inside pump as long as its protected from freezing temperatures.

1- Pressure switch located on top to "read" the hydrostaric pressure above the pump housing. 2- A float preset to a desired height to keep the water level from over flowing the sump pit.