A KNAUER pump is normaly protected against high pressure in two different ways. If a pressure sensor is provided at the pump, you can set a maximum pressure on which the pump will stop pumping if reached. If no pressure sensor is installed like in a P 2.1S pump you can also set a maximum power supply above which the pump will also automatically stop pumping. Both settings can be changed to fit at best your applications. For further protection of your HPLC system we also advise you to install a proper pressure release valve. Please visit our corresponding product selection webpage or contact us (firstname.lastname@example.org) to choose the right one.