Medium
C4 (ΔP-C) on Alpha H25 Xtraflame

Your boiler's internal pump is currently running at a fixed, constant speed rather than adjusting to the needs of your heating system.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Constant curve - H=4 m (Orange LED)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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