La Marzocco GB5 / Linea Classic Anti-Valve – Genuine OEM Replace a faulty anti-valve (vacuum breaker) on your La Marzocco GB5 or Linea Classic with this genuine OEM part. The anti-valve prevents a vacuum forming in the boiler as it cools, which could otherwise draw water back through the system or cause boiler damage. A failed anti-valve can cause boiler vacuum issues, water siphoning, or steam leaks. Compatibility La Marzocco GB5 La Marzocco Linea Classic Symptoms of a Faulty Anti-Valve Boiler vacuum forming when machine cools down Water siphoning back through the system Steam or water leaking from the anti-valve body Visible damage or corrosion on the valve Frequently Asked Questions Is this a genuine La Marzocco part? Yes, this is a genuine OEM La Marzocco anti-valve for the GB5 and Linea Classic. Can I replace this myself? Anti-valve replacement requires draining the boiler and working with pressurised fittings. We recommend this be carried out by a qualified technician. Our Sydney-based team can assist — contact us to book a service.