Worcester Bosch EA Fault Code: Causes & Easy Fixes

Overview & Key Takeaways

On Worcester Bosch boilers\u2014including the Greenstar i, Si, Ri, 4000, and 8000 series\u2014the **EA fault code** is the single most frequent error code reported by homeowners.

Technically, an EA code indicates: **"Flame Not Detected After 4 Ignition Attempts."** The boiler attempted to spark and establish a stable gas flame four times, but its internal flame sensing probe detected zero combustion, causing the control board to lock down the appliance as a safety precaution.

3 Steps You Can Safely Check Yourself

Before calling for emergency assistance, perform these three safe checks: 1. Verify Your Gas Supply: Check whether other gas appliances in your home (such as a gas hob) are working. If you have a prepayment gas meter, check that it has not run out of credit or entered an automatic safety shutoff state. Also check that your yellow emergency gas isolation handle at the meter has not been bumped into the off position. 2. Inspect the Condensate Pipe for Freezing: If it is winter and the temperature outside is below freezing, check your external plastic condensate drain. If the pipe is frozen, water has backed up into the combustion chamber, drowning the spark electrode and triggering an EA lockout. Thawing the pipe (as detailed in our freezing guide) will immediately clear the fault. 3. Execute the Reset Sequence: On the front control panel, press and hold the Reset button (or the reset key on newer Greenstar 4000 full-colour screens) for 3 to 5 seconds. The boiler will execute an internal pre-purge cycle. If the gas supply is restored, the boiler will ignite and resume normal heating.

When You Must Call a heating engineer

If your gas supply is active, the condensate pipe is clear, and the boiler fails to ignite after two reset attempts: STOP. Continually pressing reset will flood the combustion chamber with unburned gas.

An independent qualified heating engineer must inspect the internal components: - Fouled or Corroded Flame Sensing Probe: Over years of operation, carbon deposits coat the sensing electrode, preventing it from detecting the micro-amp electrical current generated by the flame. - Faulty Gas Solenoid Valve: If the motorized gas valve fails to open, gas cannot reach the burner. - Flue Obstruction: A blocked external flue terminal restricts oxygen intake, preventing ignition.

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