Nivona express 830 - No frothing milk when making latte one by one

The discussion addresses a recurring issue with the Nivona 830 espresso machine where milk frothing fails when making multiple lattes consecutively. The first latte produces properly frothed milk, but subsequent attempts result in milk spraying without foam. The primary cause identified is malfunction or clogging of the valve between the boiler and the bleed valve, often requiring cleaning or replacement. Additional critical components include the non-return valve, ceramic valve with a small aeration hole, and the cappuccinator (milk frothing spout). Cleaning these parts thoroughly, especially the rubber valve with a small hole that can become clogged, improves performance. Some users replaced the non-return valve and aerator gasket, which restored proper frothing. The ceramic valve gasket and screws may also need maintenance or replacement to prevent air leaks. The aerator assembly, including the gasket, sheet metal plate, and plastic cap, is crucial for correct air supply during frothing; improper fitting causes excessive air intake and splashing. Descaling the system and lubricating valve components can help but may offer only temporary relief. The steam and air hoses connected to the frother head function together to draw air via vacuum during steam flow. Persistent issues often require valve replacement, with original parts available online. Photos and part numbers (e.g., 6760015 / 6761179) were shared for reference. The problem is common among used Nivona 830 machines and similar models like Nivona 758 and 855.
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