BoilerFaultCodesVokera AL71 Fault Code
The Vokera AL71 fault code means: your boiler has detected an issue with the sensor that monitors the temperature of the water leaving the unit, causing it to shut down as a safety precaution.. It appears on 6 Vokera models in our database.
Technical description: Primary (flow) thermistor fault
What causes the Vokera AL71 fault?
This fault occurs when the boiler's internal computer receives an incorrect or missing signal from the sensor that tracks how hot the water is. The most common reason is that the sensor itself has worn out and failed, though it can also be caused by a loose connection or damaged wiring. Because the boiler no longer knows the exact temperature of the water, it shuts down to prevent the system from overheating.
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 AL71 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera AL71 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