If there were no water at the discharge of a pump and then you had just fed water through and measured the pressure of the gauge...would that be a different pressure if the whole system (both inlet and outlet) were continuously filled with water?
1.If there is no water at the discharge of the pump then there can be no pressure. 2. If there is water at the discharge of the pump, but the pump is not running, then there will be a pressure in the system. 3. If the pump is running, the pressure in the system will be higher than at 2.) above becuse it takes additional pressure to move the water through the piping. The flowing water requires additional pressure to get thru the piping system.
