BoilerFaultCodesAlpha 0A80 Fault Code
The Alpha 0A80 fault code means: your boiler is having trouble communicating with its internal temperature sensors, which means it cannot accurately measure how hot the water is and has stopped working as a safety precaution.. It appears on 3 Alpha models in our database.
Technical description: Flow and return sensor connection fault. Fault may occur after several minutes of boiler operation.
What causes the Alpha 0A80 fault?
This fault occurs when the boiler's control board receives conflicting or missing data from the sensors that measure water temperature entering and leaving the unit. The most common reason is that one of these sensors has physically failed or the electrical wiring connecting them has become loose or damaged over time. Because the boiler cannot accurately track how hot the water is, 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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Gas Safe Register →Alpha models that show the 0A80 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Alpha 0A80 fault code information on this page is sourced and cross-checked against the official Alpha service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026