Vaillant Water Filter 010052

The Vaillant 010052 is a water filter used in Vaillant MAG 125 and MAG 9 series water heaters. It sits in the cold water inlet path and traps scale, grit and debris before the water reaches the appliance's internal components. Its role is to protect the heat exchanger and waterways from particulate build-up that would otherwise reduce performance and shorten service life.

• Reduced hot water flow at the outlet, with the cold supply confirmed as adequate
• Grit, scale particles or discoloured water appearing at hot taps
• Visible debris or heavy scale build-up on the filter element during servicing
• Repeated scale-related faults or poor appliance performance despite correct servicing
• Water weeping from the filter housing or its connection points

• Confirm your appliance model against the fit list above, as several MAG 125 and MAG 9 variants are covered
• Check the part number on the existing filter or in the manufacturer's parts list for your model
• Inspect the filter housing and seals while the appliance is drained, and replace any worn sealing components as required
• Confirm the filter location on your appliance before dismantling, as access differs between models