BoilerFaultCodesVokera b29 Fault Code
Also written as B29 — same fault.
The Vokera b29 fault code means: your boiler has stopped working because the fan used to clear out waste gases is not communicating correctly with the main control board.. It appears on 1 Vokera model in our database.
Technical description: Incorrect signal from fan
What causes the Vokera b29 fault?
This fault occurs when the boiler's main computer loses the ability to accurately control or monitor the speed of the fan. It is usually caused by an internal electronic failure within the fan motor itself or a loose connection in the wiring that carries signals between the fan and the control board. Without a reliable signal, the boiler shuts down as a safety precaution to ensure waste gases are being properly extracted.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Vokera models that show the b29 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera b29 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 27 April 2026