The Interpump S3 safety relief valve is a manually-adjustable, pressure-operated device which, according to its setting, releases the excess of water when the pressure inside the pump/system exceeds the adjusted value, thus reducing the pressure. The normal working conditions can be restored by turning off and then restarting the system. 60-700 Bar pressure. 10-100 Lpm flow. 60°C max water temperature. Brass body - Stainless steel internals. Not preset, see manual. 1/2"BSPM inlet.