BoilerFaultCodesVokera AL34 Fault Code
The Vokera AL34 fault code means: your boiler has stopped working because it cannot correctly detect if the internal fan is spinning at the right speed to safely clear away exhaust fumes.. It appears on 6 Vokera models in our database.
Technical description: Fan tacho signal fault
What causes the Vokera AL34 fault?
This fault occurs when the boiler's main computer loses track of how fast the internal fan is spinning, which is a vital safety check. It is typically caused by a buildup of dust and debris slowing the motor down, or a failure in the electronic sensor that reports the speed back to the system. If the fan can't be verified as working correctly, the boiler shuts down to prevent dangerous exhaust gases from staying inside the unit.
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 AL34 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera AL34 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 31 August 2026