[RMcNeal]

I make sure the water heater bypass is NOT engaged, then hook up with normal flow. When I can't hear water running in the water heater anymore, usually about 2 minutes or so, I go inside and run hot water in kitchen and bath room. Granted, the water is cold since heater isn't on, but that gets air out of the hot water lines and ensures the water heater is full.
Then switch over to power fill and fill the FW tank as desired, typically until it runs out the side. This also makes sure all your lines, cold and hot, are full of water too.
BTW, you don't want or need the water pump on for this process. The city connection pressure will do the work for you.