Boiler displays E1 227, attempts to ignite but fails, then locks out. You may hear the fan run but no flame is established.

Safety first: Isolate power and gas if you suspect a leak. Do not open the combustion chamber unless qualified.

User checks:

• Confirm gas supply to the property is available and other gas appliances work.
• Reset the boiler and listen for normal ignition sequence (fan, click, then flame). If it repeatedly fails, stop resetting.
• Check flue terminal is clear of obstructions.

Engineer actions:

• Inspect and clean the flame sensor electrode; ensure it is correctly positioned in the flame.
• Check boiler earth continuity and tighten all earth connections.
• Measure gas inlet and burner pressure; adjust or replace the Worcester gas valve if readings are incorrect.
• Remove and inspect the burner and injector for debris or corrosion; clean or replace as required.

This code usually requires a Gas Safe engineer to test and adjust combustion safely.