Flojet - 4000 Series High Flow Quad PumpFloJet 4000 Series High Flow Quad Pump for On Demand Water Delivery Four piston diaphragm design with self priming capability and automatic pressure control for residential and light commercial applications Self Priming to 2. 4m 4. 8 GPM Flow Rate 45 PSI Max Pressure 115V AC Motor The FloJet 4000 Series uses a four piston diaphragm architecture to deliver up to 4. 8 gallons per minute at pressures reaching 45 psi, with integrated pressure switch