http://img849.imageshack.us/img849/9018/curvess.jpg [Broken] So pump curve, as flow increases, pressure drops. For the system curve, it's the other way around. How come? How come the pump disobeys the way the system is supposed to behave? The pump is a part of the system, and in the physical world, the more pressure there is, the better is the flow. I don't understand how come in the pump the more pressure there is, flow drops!