BoilerFaultCodesAlpha 59 Fault Code
The Alpha 59 fault code means: your boiler is struggling because the electricity supply coming from your mains is not stable or is fluctuating outside of the normal range it expects.. It appears on 6 Alpha models in our database.
Technical description: Mains supply voltage frequency block - The PCB detects an incorrect mains supply voltage frequency
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Alpha models that show the 59 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Alpha 59 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 7 July 2026