When air becomes trapped in a sealed heating system it can cause a wide variety of problems including excessive noise, corrosion and increased maintenance costs as it also can cause air locks and prevent the system from operating effectively and efficiently. Automatic air vents are most suited for heating systems and other closed circuit hot water systems which require an efficient and automatic removal of air whilst the system fills with water. A vacuum break is fitted onto the bottom of the valve in order to prevent an air lock forming and encourages air to be released from the water within the system. The Reliance Automatic Air Vent are high-quality solid brass & heat resistant polypropylene to provide long life and durability in heating systems to help vent air when commissioning a system. Available with MBSP, compression or push-fit connections. Automatically vents trapped air from within sealed heating systems Robust solid brass construction and heat resistant polypropylene float Available with a variety of connection ends