Air Flow Monitor High

Baxi Air Flow Monitor Fault Code

Also written as AIRFLOWMONITOR — same fault.

The Baxi Air Flow Monitor fault code means: your boiler has detected a problem with how it is venting waste gases or taking in fresh air, causing it to shut down for safety.. It appears on 1 Baxi model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: The neon illuminates to indicate that the flue or flue terminal is blocked or obstructed in some way, or that there is an internal fault.
Typical repair cost £100-280 (including labour)

DIY fix possible

Check the flue terminal outside your property to ensure it is not blocked by debris, leaves, or snow.Inspect the terminal mesh for any bird nests or physical obstructions.Restart the boiler using the selector switch to see if the fault clears.

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Baxi models that show the Air Flow Monitor fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Baxi Air Flow Monitor fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026