Priming the pump?

What does that mean? I have a Dynamo 1hp pump, and a Star DE filter. As soon as my water level is 1/2 way up the skimmer, I was going to just flip the switch to start the system going. I know I have to put the 4lbs. of DE into the skimmer within 2 minutes of turning the pump on (said so in the filter directions), but I know nothing else as to how to start this whole system up...specifically what priming the pump means. Also, my filter instructions gave no info about backwashing. Could it be that my filter doesn't backwash? It did say about how to "bump" the filter when the pressure drops 10psi's lower than the start up pressure. Thanks!

Priming a pump simply means adding water directly to the pump basket to 'wet' the impeller and pump chamber, and give it something to pump initially. If the pump is above the water level it needs to pull enough of a vacuum to suck the water into the pump basket. When the pump is totally dry, the clearance between the impeller and the housing is too great to generate this vacuum. All the thing is doing is kicking air around...even self priming pumps probably won't pull water when totally dry. It all depends on the pump type and how high above water level the pump is located. Another factor controlling how much vacuum it can pull is what is on the pressure or output side of the pump but the way most systems are plumbed this isn't usually a show stopper to starting flow. Alsd note that is may take a few minutes of running to get the water flowing. Procedure is to just fill the pump basket with water as much as you can, close and tighten the lid, and fire the thing up.
Hope this answers your question.
Al

Thank you Al! I think mine primed itself because the water basket is already filled with with water and the pump is off. I know my water level has to be 1/2 way up the skimmer in order for the whole operation to work and it's not quite there yet. However, it is about 1 inch into the skimmer and it seems just that amount has been sufficient to prime the pump (my pump sits on the ground at the base of the pool so I imagine this is why). Thanks again! One less thing to stress over. :o

Fire it UP!!!!!
With an inch in the skimmer, you should be good to go! If it creates a big vortex and starts sucking air, wait a bit more, but you should be good.
I have a large rock in my basket to keep the basket in place when the pump cycles on/off - this helps break the vortex so it does not suck air.
My neighbour uses trichlor tabs when he's lower on water to do the same for him. For the amount of acid that dissipates off the tabs over any given period of time, you should never have an issue with pump seals etc due to acid corrosion, there just isn't a high enough concentration.
As for priming, an AG pool self primes beacuse the pump is lower.
Sometimes if there's too much air in the vac line and you just cleaned out your pump basket, it can cause the pump to have issues priming, I just run the pump first to get it full with water, then connect up the vac, it usually works.