The D-025 Combination Air Valve combines an air & vacuum orifice and an air release orifice in a single body. The valve is specially designed to operate with liquids carrying solid particles such as wastewater and effluents. The combination air valve discharges air (gases) during the filling or charging of the system, admits air into the system while it is being emptied of liquid and releases accumulated air (gases) from the system while it is under pressure and operating. The valve’s unique design enables the separation of the liquid from the sealing mechanism and assures optimum working conditions. D-025 Sewage Air Valves ARI by Aquestia Brochure