The eheim 2222 is one of the "Pro" series, not the "Pro2" series. It does indeed have separate baskets for media (which is a great feature and they work well) but it does not have a built-in priming plunger as the Pro2 series do. I actually consider this a "plus" of sorts as it is sometimes reported that priming features are among the first thiTngs to cause a filter to need servicing (the flexible bellows crack and break I think.)
There is an accessory you can order from eheim for priming. Its a black rubber squeeze ball with a green cone that nicely fits the eheim tubes and it has a little piece of side air tubing. If you need to prime you simply slip the tubing off your spraybar and give a few suction squeezes with this little ball. The thing is, I've hardly ever needed to use this primer, as usually when I plug the eheim back in it just seems to instantly prime itself and and all is flowing again, so its really only been after a filter clean, and even then seems not much needed.
I also consider the non-thermo versions of the eheim pro & pro2 models to be a better choice than the thermo ones that have built-in heaters. There were too many failures of the thermo sensors when people had any salt in their water. Better to just use a Hydor inline if you want "stealth" heating in your tank.
~~waterdrop~~