BoilerFaultCodesAlpha 0E46 Fault Code
The Alpha 0E46 fault code means: your boiler has detected that the exhaust temperature is being measured incorrectly and has shut itself down as a safety precaution.. It appears on 3 Alpha models in our database.
Technical description: Flue sensor out of range. Flue sensor measures a temperature outside normal working range.
What causes the Alpha 0E46 fault?
This fault occurs when the internal sensor responsible for monitoring exhaust temperature signals a reading that is physically impossible or dangerously high. The most common reason is a failing sensor sending incorrect data, but it can also be triggered by a build-up of debris or scale within the heat exchanger causing the system to overheat.
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 0E46 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Alpha 0E46 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