24 High

Vaillant 24 Fault Code

The Vaillant 24 fault code means: your boiler is failing to light the flame properly, which means it will stop working to keep your home warm and provide hot water until it is repaired.. It appears on 1 Vaillant model in our database.

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: Ignition electrode
Typical repair cost £150-280 (including labour)

Engineer required

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

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Vaillant models that show the 24 fault code

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

Source

Vaillant 24 fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026