BoilerFaultCodesVokera 34 Fault Code
The Vokera 34 fault code means: your boiler is failing to start because it cannot detect that the internal air extraction system is running correctly.. It appears on 4 Vokera models in our database.
Technical description: fan error (start-up)
What causes the Vokera 34 fault?
This fault occurs when the boiler's internal computer detects that the fan is spinning at an incorrect speed or the air flow isn't being measured correctly. The most common reason is a small blockage or moisture buildup in the thin silicone tubes that monitor pressure, or the fan itself may be starting to wear out and struggle to reach the required speed.
This issue can be more frequent during periods of high wind or extreme cold, as external air pressure changes or frozen debris in the flue can interfere with the fan's air flow sensors.
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 34 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera 34 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