BoilerFaultCodesAlpha 0A15 Fault Code
The Alpha 0A15 fault code means: your boiler's temperature sensors are giving conflicting readings, causing the system to stop operating to prevent potential damage.. It appears on 3 Alpha models in our database.
Technical description: Flow and return sensor anomaly detected. The sensor shows an incorrect temperature value.
What causes the Alpha 0A15 fault?
This fault occurs when the boiler's control board receives conflicting information from the two probes that monitor water temperature. It happens because one of the sensors has likely degraded and is sending an inaccurate electrical signal, making the boiler think the internal heat levels are unsafe. The system shuts down as a precaution because it can no longer accurately track how much heat is being transferred into your radiators.
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 0A15 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Alpha 0A15 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