47 Low

Alpha 47 Fault Code

The Alpha 47 fault code means: your boiler is still working but cannot reach its full power, meaning your radiators might not get as hot as they should.. It appears on 24 Alpha models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Reduced burner output

What causes the Alpha 47 fault?

This fault occurs when the boiler's control system detects that the burner cannot maintain its regular intensity, forcing it to operate at a lower power level. The most common reason is that the boiler is struggling to accurately monitor or control the gas flow and flame strength required for full heat. While the boiler stays on, it cannot generate enough energy to satisfy high demands for heating or hot water.

This issue is often more noticeable during winter when the boiler is expected to work at maximum capacity to heat a cold home.

Typical repair cost £100-£250 (including labour)

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 47 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Alpha 47 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