The boiler tried to light but did not detect a flame, so it has locked out for safety.
Most common on: Greenstar i, CDi Classic, Greenstar Lifestyle
EA is the most common Worcester Bosch fault code. It means the boiler went through its ignition sequence but the flame-sensing electrode did not detect a stable flame, so the control board shut the gas valve and locked out.
It is a safety lockout, not a random error — the boiler is deliberately refusing to keep sending gas when it cannot confirm a flame. A single lockout can be cleared with a reset, but a boiler that locks out on EA repeatedly has an underlying fault that needs an engineer.
Make sure a gas hob or another gas appliance lights. If nothing gets gas, the problem is the supply — check the gas cock at the meter is on and that a prepayment meter has credit.
The isolation lever under the boiler should be in line with the pipe (open). If it is turned across the pipe, the gas is shut off.
Press and hold the reset button for a few seconds. If the boiler fires and stays lit, it was a one-off lockout. If it locks out on EA again, stop resetting it repeatedly.
In cold weather a blocked or frozen condensate pipe (the white plastic pipe running outside) can trigger a lockout. Thawing it can clear the fault — but if you are unsure, call an engineer.
Repeated EA lockouts point to the electrode, gas valve, PCB or gas pressure — all of which need a Gas Safe registered engineer with the right test gear.
Work on the gas side of a boiler must be carried out by a Gas Safe registered engineer. The checks above are limited to safe, non-invasive things a homeowner can look at (pressure, resets, the gas supply) — if in doubt, stop and call an engineer.
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The boiler tried to light but did not detect a flame, so it has locked out for safety. EA is the most common Worcester Bosch fault code. It means the boiler went through its ignition sequence but the flame-sensing electrode did not detect a stable flame, so the control board shut the gas valve and locked out.
You can try a single reset and the safe checks below, but Worcester Bosch EA usually needs a Gas Safe registered engineer. Never work on the gas side of a boiler yourself — it is illegal and dangerous unless you are Gas Safe registered.
A recurring EA means the underlying cause has not been fixed — most often no gas reaching the boiler (gas cock off, meter credit run out, or the wider gas supply interrupted). Resetting repeatedly will not solve it; get the boiler diagnosed properly.
No flame detected
Pump / circulation fault (dry fire protection)
Fan fault
See all Worcester Bosch fault codes.