High
20 on Alpha C25 Xtraflame

Your boiler is confused because it thinks a flame is burning when it shouldn't be, or it cannot confirm the flame is lighting correctly, causing it to shut down for safety.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Flame sensing fault - False flame detection / Flame detected but gas valve is not open

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

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