How does my Inground pump operate?

The Hayward in-ground pumps have a vaccumm chamber that must be filled with water in order to create a vaccuum, to take the water out of your pool.  The housing stays full of water while the pump is turned on, and remains pretty much the same when it is turned off as well.  Hayward 2-speed pumps will turn on to a pre-selected speed, but sometimes it will turn on to “high” and then make its way down to a low speed.
All Hayward in-ground pool pumps have a diffuser in them which allows for the self priming.  As the air is taken out of the system, bubbles will start to form.  You will know when the self prime has occurred because the bubbles will stop and the pump basket will now be full of water. 
Thes Hayward pumps for your in-ground pool are very simple and easy to understand and operate.  They do require lots of water supply from your pool, without any air from the suction lines.