Boiler displays E1 227, attempts to ignite but fails, often after running out of gas or after gas supply interruption.

Safety first: Do not repeatedly reset the boiler if you can smell gas. Turn off the gas at the meter and call the gas emergency number. Only Gas Safe engineers should work on gas components.

User checks:

• Confirm your gas meter credit (if prepay) and that the gas isolation valve is fully open.
• Check other gas appliances work normally.
• Press the reset button once and allow the boiler to complete a full ignition sequence.

Engineer actions:

• Bleed air from the gas pipework by safely purging at an appropriate test point, following gas regulations.
• Measure inlet and burner pressure at the gas valve and compare with Worcester Bosch data plate values; correct supply or adjust valve as required.
• Inspect and test the ionisation electrode and lead; replace if cracked, contaminated, or giving weak signal.
• Check the gas valve coil resistances and wiring harness back to the main PCB; repair or replace as necessary.
• Confirm correct polarity and earth at the boiler supply, as poor earthing can affect flame detection.