I would recommend hooking up to the city water and get all the air out of the lines and water heater with the city hook up. Open your grey water tank waste valve and let it run on the ground (it clean water running through there anyway) so you don't fill your grey tank. After your satisfied that the air is all out of the lines you can switch over to your water pump. If your pump wont do it's job at this point, there's an air leak or valve turned wrong. I had a simular problem with my Redwood and I found that the problem was the rubber gasket under the weatherization cap was missing. This allowed air to be sucked into the lines.