Worcester Bosch EA Fault Code: Causes, Fixes & Repair Costs
What does the Worcester Bosch EA fault code mean?
EA on a Worcester Bosch boiler is an ignition lockout: the boiler tried to light its burner — typically up to four attempts — and could not confirm a stable flame on any of them, so it shut down rather than keep releasing gas it cannot light. It is the most common Worcester code by a distance, and on the Greenstar 4000, 8000 and CDi ranges it is almost always paired with a three-digit sub-code (EA 227, EA 229 and so on) that narrows the cause — EA 227 is 'never lit', EA 229 is 'lit, then lost the flame'. In winter the cause is usually outside the boiler: a frozen condensate pipe or an interrupted gas supply. Check those two, reset once, and if EA returns, book a Gas Safe registered engineer.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Gas supply interrupted or off Common
If the gas supply to the property is disrupted — due to a regional outage, a closed isolation valve on the supply pipe, or a prepayment meter that has run out of credit — the boiler simply has no fuel to ignite. Test another gas appliance such as your hob: if that also fails to light, the fault lies upstream of the boiler entirely rather than inside it.
- Faulty or worn ignition electrode / flame sensor Common
The ignition electrode creates the spark that lights the gas, while a separate flame-sensing electrode (or the same combined component) confirms the flame is present. Both can degrade over time through carbon build-up, corrosion, or physical misalignment. Even a slightly dirty or displaced electrode can prevent a reliable spark or cause the boiler to fail to recognise a flame that is actually present. This is one of the most frequent causes engineers find when attending an EA fault.
- Frozen or blocked condensate pipe Common
Condensing boilers expel acidic waste water through a plastic condensate pipe, which often routes externally. During cold snaps, the water inside can freeze and cause a back-up that triggers a lockout — sometimes logged as an EA code. Look for a white plastic pipe exiting the boiler to an outside wall or drain; visible frost or ice around it is a strong indicator.
- Faulty gas valve Sometimes
The gas valve meters the precise amount of gas entering the burner. If the valve sticks, fails to open fully, or its actuator coils develop a fault, insufficient gas reaches the burner and no stable flame can form. The boiler then locks out after exhausting its ignition attempts. This component requires a Gas Safe engineer to diagnose and replace.
- Restricted flue or blocked air intake Sometimes
The boiler needs a clear path to draw in fresh air and expel combustion gases through the flue. A bird's nest, debris, or ice at the flue terminal can restrict airflow enough to destabilise combustion or prevent ignition entirely, triggering the EA lockout. Check the outside flue terminal for obvious obstructions without climbing or working at height.
- Faulty fan Sometimes
Before ignition can begin, the boiler's fan must reach a set speed to prove the flue is clear and ventilation is safe. If the fan is failing — through worn bearings, a seized motor, or electrical fault — the boiler will not proceed to the ignition stage. A C6 code may appear alongside EA on some models when the fan is the root cause.
- PCB (printed circuit board) fault Rare
The PCB orchestrates every stage of the ignition sequence. On rare occasions the board itself develops a fault — through age, moisture ingress, or a component failure — that causes it to misread sensor signals or fail to trigger ignition correctly. PCB faults tend to produce other accompanying error codes and are usually only confirmed after all other components have been ruled out.
How to fix it
- Check that other gas appliances are working DIY safe
Turn on your gas hob or check another gas appliance in the property. If nothing gas-powered works, you likely have a supply issue unrelated to the boiler. Contact your gas supplier or check whether your prepayment meter needs topping up. Also confirm the gas isolation valve — usually a lever or handle on the gas pipe near the meter — is fully open (handle in line with the pipe).
- Look for a frozen condensate pipe DIY safe
During cold weather, locate the white plastic condensate pipe where it exits the boiler and runs to a drain. If you see ice or frost on or around it, thaw it by carefully pouring warm (not boiling) water along the pipe. Repeat until water flows freely, then proceed to reset the boiler. Consider lagging the pipe afterwards to prevent a repeat freeze.
- Reset the boiler once DIY safe
Once you have completed the checks above, attempt a single reset. On most Worcester Greenstar models this involves turning the main dial to the reset position and holding it for a few seconds, or pressing a clearly labelled reset button. The boiler will then run through its ignition sequence. If it fires up and runs normally, monitor it over the next hour. If the EA code returns, do not reset it again — further repeated resets can accelerate wear on ignition components and the PCB, potentially turning a straightforward repair into a more expensive one.
- If the fault persists, call a Gas Safe registered engineer Gas Safe engineer
A persistent EA fault — or one that clears on reset but keeps returning — needs professional diagnosis. A registered engineer will check gas supply pressure at the appliance, inspect and test the ignition electrode and flame sensor, examine the gas valve operation, and assess the fan and flue for any restrictions. They will also read any detailed sub-codes (such as EA 227) from the boiler's internal fault log to pinpoint the exact failure point. Do not attempt to open the boiler casing or interfere with gas components yourself.
EA sub-codes explained (EA 227, EA 229, EA 234, EA 261, EA 269)
Modern Worcester boilers show EA together with a three-digit sub-code, and the sub-code is the useful half. Note both before you reset.
| Code | What it means | Where to look first |
|---|---|---|
| EA 227 | No flame detected during ignition — the burner never lit | Gas supply, condensate pipe, ignition electrode |
| EA 229 | Flame established, then lost while running | Gas pressure under load, flame-sense electrode, flue/wind |
| EA 234 | Flame/ignition failure within the EA family | As EA 227, plus gas valve |
| EA 261 | Failed to establish or confirm a stable flame | Electrode, ionisation lead, PCB flame circuit |
| EA 269 | No stable flame after repeated attempts | Gas supply and pressure, electrode |
If your boiler shows EA with no sub-code (older Greenstar i, Si and CDi models with a simpler display), the general guidance on this page applies and the engineer will read the sub-code from the boiler's service menu.
EA in cold weather: the frozen condensate pipe
Every condensing Worcester produces a trickle of acidic water that drains through a plastic condensate pipe. Where that pipe runs outside, a hard frost freezes it, the condensate backs up into the boiler's siphon, and the boiler will not light — presenting as EA (usually EA 227), often after some gurgling. It is the single biggest cause of winter EA lockouts on the Greenstar range.
Thaw the exposed pipe with warm (not boiling) water or a hot-water bottle, wait for the trickle, then reset. If that fixes it, have the pipe lagged, re-routed or fitted with a trace-heating cable before the next cold snap — Worcester's own CondenseSure kit exists for exactly this.
Worcester boiler flashing EA — what the display is telling you
On the Greenstar 4000, 8000 and CDi the display shows EA (with the sub-code alternating or beneath it) and a spanner or warning symbol; the blue-ring models show it in the small central display. A flashing EA means the boiler has locked out and is waiting for a reset — it will not retry on its own. That is deliberate: the boiler limits its own ignition attempts so it never keeps admitting gas against a fault. Reset it once from the front panel; if EA comes back straight away, the fault is real.
What the engineer will check, in order
A methodical EA diagnosis runs cheapest-first. Gas first: is there a supply and is the working pressure at the boiler's test point correct under load (a lit-then-lost EA 229 often points here). Then the ignition electrode and lead — the electrode's gap, its ceramic and any deposits, and the strength of the spark. Then flame detection: the ionisation signal once the burner lights. Then airflow: the flue, its terminal, and the fan. Only then the gas valve and, last, the control board.
After any ignition repair the engineer should run a combustion check with a flue-gas analyser — a boiler that has been struggling to light may have been running with poor combustion for weeks.
Parts you may need
- Ignition electrode · from £25
- Ignition lead · from £15
- Condensate pipe lagging / trace heater · from £15
- Gas valve · from £140
- Control PCB · from £220
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £0–£350, depending on the underlying cause.
Frequently asked questions
What does EA mean on a Worcester Bosch boiler?
EA is an ignition lockout — the boiler tried to light (up to four times) and could not confirm a flame, so it shut down. Check the gas supply and, in winter, the condensate pipe; reset once; call a Gas Safe engineer if it returns. Modern models add a sub-code (EA 227, EA 229) that narrows the cause.
What does EA 227 mean on a Worcester Bosch boiler?
EA 227 is the most common EA sub-code: the burner never lit at all — no flame detected during the ignition sequence. Gas supply, a frozen condensate pipe and a worn ignition electrode are the usual causes, in that order.
What is the difference between EA 227 and EA 229?
EA 227 means the boiler never established a flame; EA 229 means it lit successfully and then lost the flame while running. EA 229 points more toward gas pressure dropping under load, a tired flame-sensing electrode, or wind and flue problems, rather than the supply being off.
Can I fix the EA fault myself?
The two commonest causes are homeowner-fixable: restoring the gas supply (meter credit, emergency control valve) and thawing a frozen condensate pipe. Anything inside the boiler — electrode, gas valve, fan, PCB — is Gas Safe registered work by law.
Why does my Worcester keep showing EA after I reset it?
Because the cause is still there. Each reset is a fresh attempt to light; if the gas is off, the condensate pipe is still frozen, or the electrode is worn, it will fail again. Stop after one reset and diagnose — repeated attempts can flood the combustion chamber.
How much does a Worcester Bosch EA fault cost to fix?
From nothing (thawed pipe or restored gas) through roughly £100–£180 for a call-out and new electrode, to £250–£350 if the gas valve, fan or PCB is at fault. Regional rates and emergency call-outs vary — get a written quote, and check whether the boiler is still under Worcester's guarantee.
Does EA mean the boiler is unsafe?
The lockout is the safety system doing its job — the boiler stopped because it could not prove a flame. The one thing never to ignore is a smell of gas: if you can smell gas, leave the property and call 0800 111 999.
Is the EA code on a Viessmann the same fault?
Viessmann also uses EA for repeated failed ignition, but the boilers are entirely different and the sub-codes on this page are Worcester-specific. See the Viessmann EA page, or compare EA across brands.