High
C3 (ΔP-C) on Alpha H25 Xtraflame

Your boiler has detected an issue with the internal water pressure or circulation flow, meaning it cannot safely heat your home or water.

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

Constant curve - H=3 m (White LED)

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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