Suttner ST-280 Unloader Valve. Used to protect the pump. Should the operating pressure exceed the pressure the unloader is set at, the unloader will act as a pressure regulator and dump excess water to ensure the adjusted pressure is not exceeded. Whenever the trigger gun is shut off the unloader will switch to bypass and send excess water back to the pump low pressure water inlet , or supply barrel depending on your set up. Straight flow-through design minimizes pressure loss through valve. Working components constructed of high-grade stainless steel. Teflon and Viton seals for maximum heat and chemical resistance. Internal bypass valve can be easily accessed and repaired without removing unloader from unit. Max Pressure 250 Bar. Max Flow 30 L/Min. Max Temperature 80°C. Inlet 3/8" Female. Outlet 3/8" Female.