A 09 High

Vokera A 09 Fault Code

Also written as A09 — same fault.

The Vokera A 09 fault code means: your boiler has detected an issue with the sensor that monitors exhaust gases or internal heat, forcing it to shut down for safety.. It appears on 2 Vokera models 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: Failure flue sensor, cleaning primary exchanger
Typical repair cost £150-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Vokera models that show the A 09 fault code

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

Source

Vokera A 09 fault code information on this page is sourced and cross-checked against the official Vokera service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026