| Most pumps are self-priming centrifugal pumps. | | | | When you turn on the pump the motor will begin |
| These pumps must have a vacuum chamber, | | | | to rotate on high speed (dual speed pumps rotate |
| commonly known as a pump housing. The pump | | | | at the preselected speed). The motor drives the |
| housing must be filled with water in order for any | | | | pump impeller, located inside the pumps center |
| pump to create a vacuum, resulting in your pump | | | | portion at the opposite end, away from the |
| pulling the water out of your pool or spa. The | | | | electrical switch portion of the motor. While the |
| pump housing will remain full of water while the | | | | motor is rotating, the tips of the impeller are |
| pump is on, and will remain full or partially full of | | | | sealed hydraulically inside of the pump diffuser, |
| water when the pump is shut off. | | | | this allows self-priming to occur. |