A 03 High

Chaffoteaux A 03 Fault Code

Also written as A03 — same fault.

The Chaffoteaux A 03 fault code means: your boiler has failed to light the flame after several attempts and has switched itself off to prevent a gas buildup.. It appears on 1 Chaffoteaux 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: After multiple attempts (following error E04), should the boiler still not sense a flame, error code A03 will appear on the LCD.
Typical repair cost £120-250 (including labour)

Engineer required

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

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Chaffoteaux models that show the A 03 fault code

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

Source

Chaffoteaux A 03 fault code information on this page is sourced and cross-checked against the official Chaffoteaux service / installation manuals for each affected model.

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