The Pratissoli SV12 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. 640-1800 Bar pressure. 12-100 Lpm flow. 30°C max water temperature. Stainless steel construction. Factory set & sealed to order. 1/2"BSPM inlet.