Pressurization unit is an engineered packaged unit designed to replace water that has been lost through system leakage and to maintain the system design fill pressure in sealed heating and chilled water systems. A basic pressurization unit may include Bladder Expansion Tank, Pump and Controller. A skid mounted unit may include several equipment such as pumps, control panel, pressure switch (or transducer, transmitter), bladder expansion tank, storage vessel w/ level switch, valves, controls & instrumentations, etc.