BoilerFaultCodesVokera b 29 Fault Code
Also written as B29 — same fault.
The Vokera b 29 fault code means: your boiler is struggling to communicate with its internal air-flow system, which prevents it from safely igniting and providing heating or hot water.. It appears on 1 Vokera model in our database.
Technical description: Incorrect signal from fan
What causes the Vokera b 29 fault?
This fault occurs when the boiler's control board detects that the fan is not spinning at the required speed to safely clear exhaust gases. It is usually caused by a mechanical failure in the fan motor, a loose connection in the wiring, or a fault on the main circuit board failing to send the correct power signal.
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 b 29 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera b 29 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