A Worcester Bosch boiler showing the EA fault code has failed to confirm a burner flame. The boiler may attempt to ignite, stop, and then lock out, leaving you without heating or hot water. On relevant Greenstar CDi models, Worcester Bosch defines EA as flame not detected.
Start by checking whether there is gas available in the property and whether freezing weather may have blocked an accessible external condensate pipe. Do not remove the boiler casing, test internal parts, or keep resetting the appliance.
Do not troubleshoot the boiler when you smell gas, a carbon-monoxide alarm has activated, the flue appears damaged, or anyone feels dizzy, sick, breathless, or unusually tired. Leave the property and follow emergency gas-safety guidance instead.
Quick Answer
| Item | Details |
|---|---|
| Fault code | EA, sometimes accompanied by a model-specific subcode |
| Meaning | The boiler has not detected or confirmed a burner flame |
| Appliance | Worcester Bosch gas boiler |
| Common starting points | Interrupted gas supply, frozen or blocked condensate drainage, or a flue problem |
| Safe first check | Confirm that gas is available and consider whether the external condensate pipe could be frozen |
| Reset | Depends on the boiler model and control panel |
| Repair difficulty | External checks are simple; internal diagnosis is professional work |
| Can the boiler keep running? | Normally no. Heating and hot water may remain unavailable while the fault is active |
| Professional help | Required when EA returns, there is no clear external cause, or an internal combustion component may be faulty |
What Does the Worcester Bosch EA Fault Code Mean?
The confirmed meaning of EA on Worcester Greenstar CDi documentation is flame not detected. The boiler control has not received the expected flame signal while trying to operate. This may mean that the burner never lit, or that a flame started but the control system could not confirm it correctly.
The code identifies the result of the fault, not necessarily the failed component. It does not prove that the ignition electrode, gas valve, flame sensor, or printed circuit board needs replacing.
Depending on the model, the display may show plain EA, EA with another number, or a different numerical fault and text description. Record everything shown on the display and use the operating manual for the exact boiler model.
What Happens When EA Appears?
You may notice one or more of these symptoms:
- The boiler clicks or attempts to start but does not fire.
- The burner starts briefly and then stops.
- The reset button or fault light flashes.
- Radiators remain cold.
- Hot water from a combi boiler becomes unavailable.
- The fault returns shortly after a reset.
- A gurgling sound occurs during freezing weather.
A gurgling sound combined with an EA display during very cold weather can point towards a frozen or blocked condensate pipe, but it is not the only possible cause. Worcester Bosch specifically notes that a frozen external condensate pipe can stop the boiler and may produce an EA code.
Common Causes of an EA Fault
1. The gas supply is interrupted
The boiler cannot produce a flame without the correct gas supply. Possible external reasons include:
- A local gas-supply interruption
- An empty prepayment meter
- A closed accessible gas isolation control
- An LPG cylinder that is empty
- Low gas pressure
Worcester Bosch lists no gas supply or low gas-supply pressure among the checks associated with an EA fault. Its newer user instructions also suggest checking whether another gas appliance, such as a hob, is working.
Do not test another appliance when you smell gas. In that situation, avoid flames and electrical switches, ventilate the property when safe, leave the building, and contact the gas emergency service.
2. The condensate pipe is frozen or blocked
A condensing boiler produces wastewater that leaves through a plastic condensate pipe. When part of that pipe runs outdoors or through an unheated area, it can freeze during prolonged cold weather.
A blockage prevents the boiler from draining correctly and can cause it to shut down. Worcester Bosch identifies ice and foreign objects at the condensate outlet as possible EA-related problems.
3. The flue outlet is blocked or damaged
The flue allows combustion products to leave the property safely. Worcester Bosch includes a blocked flue outlet among the conditions a user may check visually, provided it is safe to do so.
Only look from a safe position at ground level. Do not climb, dismantle the flue, remove a terminal guard, or attempt to clear anything lodged inside it. Flue inspection, testing, movement, and repair are jobs for a properly registered engineer.
4. The ignition electrode or cable has a fault
The ignition electrode creates the spark needed to light the gas. The associated cable and connections must also be intact.
Official Worcester service documentation includes the ignition lead, control-panel connection, cable condition, and electrode assembly in the professional diagnostic sequence for EA.
These parts are inside the appliance. Do not remove the boiler casing to inspect them.
5. The boiler cannot detect the flame
A boiler uses an ionisation signal to confirm that a flame is present. Dirt, damage, poor electrical earthing, a damaged lead, or another combustion issue may interfere with this signal.
The flame may therefore be absent, unstable, or present but not recognised correctly. Confirming the cause requires professional testing.
6. The gas valve is not operating correctly
The gas valve controls gas entering the burner. Worcester’s service documentation includes gas-valve operation, its electrical connections, the inlet filter, and gas-supply pressure in the EA diagnostic process.
This does not mean every EA fault requires a new gas valve. The engineer must test the supply and ignition sequence before deciding which part is responsible.
7. There is a combustion, air-supply, or flue fault
A problem with the flue installation, heat exchanger, air-and-gas components, or combustion settings may prevent reliable ignition or flame detection.
Worcester’s technician documentation includes flue checks, combustion measurements, fan-pressure testing, and inspection of the air-and-gas manifold. These are not homeowner procedures.
8. Wiring or the control board has failed
Damaged wiring, poor earthing, loose connections, or a control-board fault may interrupt ignition or flame monitoring.
The printed circuit board is normally considered only after the engineer has checked the gas supply, condensate path, flue, ignition parts, gas valve, and wiring.
Safe Checks Before Resetting the Boiler
Complete only the checks you can perform without opening the appliance or touching gas components.
Step 1: Look for emergency warning signs
Stop immediately when:
- You smell gas.
- A carbon-monoxide alarm sounds.
- You see soot or unusual staining near the boiler or flue.
- The flue appears loose, broken, or badly damaged.
- Someone has a headache, nausea, dizziness, breathing difficulty, confusion, or unusual weakness.
Carbon monoxide cannot be seen, tasted, or smelled. Suspected exposure requires fresh air, evacuation, and urgent professional assistance.
Step 2: Check whether gas is available
When there is no smell of gas:
- Check whether the gas meter has credit.
- Find out whether the gas supplier has reported an interruption.
- See whether another gas appliance operates normally.
- Check only an accessible user-operated isolation control that you already recognise.
Do not open the boiler or adjust an internal gas valve.
Step 3: Consider the weather
A frozen condensate pipe becomes more likely when:
- Outdoor temperatures have remained below freezing.
- Part of the plastic drain pipe runs outside.
- The EA code appeared during a cold spell.
- The boiler makes a gurgling noise.
- Ice is visible around an accessible pipe outlet.
When the weather is mild, the cause may still be a blocked condensate route, but an internal blockage should be handled by an engineer.
Step 4: Check the condensate outlet from ground level
The external condensate pipe is usually a plastic pipe running from the boiler towards a drain or waste connection.
Inspect it only when it is:
- At ground level
- Easy to reach
- Free from electrical hazards
- Accessible without a ladder
- Safe from traffic and slippery surfaces
Worcester warns users not to attempt thawing at height and not to use boiling water because thermal shock can damage plastic pipework.
Step 5: Look at the flue from a safe distance
Check for obvious external damage or an obstruction you can see without touching the flue. Do not attempt to remove debris from inside the terminal.
Step 6: Reset the correct model once
After confirming that there are no danger signs and correcting a clear external issue, one model-correct reset is reasonable.
How to Thaw a Frozen Condensate Pipe
Only proceed when the pipe is accessible from ground level.
- Locate the likely frozen section. Freezing commonly occurs at an exposed end, bend, elbow, sag, or another point where water collects.
- Apply a warm cloth, hot-water bottle, or reusable heat pack to the outside of the pipe.
- Alternatively, pour warm water over the affected area using a suitable container.
- Do not use boiling water, a naked flame, heat gun, blowtorch, or electrical appliance outdoors.
- Prevent the water from freezing on a path and creating a slip hazard.
- Once the blockage has thawed, reset the boiler using the method in its manual.
- Allow two or three minutes for the appliance to restart.
These methods follow Worcester Bosch’s condensate guidance. The manufacturer advises contacting the installer when freezing happens repeatedly so that a permanent drainage solution can be considered.
How to Reset a Worcester Bosch Boiler After EA
The reset procedure is not identical across all Worcester boilers. Check the model name and operating manual before pressing or turning anything.
| Boiler or control type | Typical reset method |
|---|---|
| Greenstar CDi Classic | Press and hold the reset button for about three seconds |
| Greenstar i System | Press and hold the reset button for about five seconds |
| Greenstar Ri and Ri ErP | Turn the central-heating control anticlockwise to RESET, hold for about five seconds, then return it to the previous setting |
| Greenstar 8000+ and 8000+ Style | Use the up and down controls until Reset is displayed |
The Greenstar CDi Classic manual specifies a three-second press. The Greenstar i System manual specifies approximately five seconds. Greenstar Ri controls use a reset position on the temperature knob, while recent Greenstar 8000+ controls use an on-screen reset selection.
After resetting:
- Wait for the boiler to complete its start sequence.
- Check whether the flame symbol appears.
- Test heating or hot water normally.
- Do not continue pressing reset when EA returns.
A reset clears the lockout and allows another ignition attempt. It does not repair a gas-supply, combustion, electrode, flue, condensate, wiring, or control-board fault.
What to Do if EA Returns After Resetting
When the boiler shows EA again:
- Stop resetting it repeatedly.
- Leave the casing closed.
- Record the full code and any number shown with it.
- Note whether the problem affects heating, hot water, or both.
- Record any clicking, gurgling, unusual fan noise, or short-lived ignition.
- Note whether the fault started during freezing weather.
- Tell the engineer whether other gas appliances are working.
- Find the boiler model details without removing a sealed or screwed casing.
- Arrange professional diagnosis.
Worcester’s manuals advise contacting support or a qualified engineer when the fault cannot be cleared through the specified reset procedure.
Parts and Systems an Engineer May Test
| Area | Why it may produce EA |
|---|---|
| Gas supply and inlet pressure | The burner may not receive enough gas to ignite reliably |
| Ignition electrode | A weak or absent spark may prevent ignition |
| Ignition cable and connections | Electrical damage or a loose connection may interrupt the spark |
| Flame-detection electrode | The control may not confirm that a flame is present |
| Gas valve | Gas may not be released correctly during the ignition sequence |
| Internal condensate trap | A blockage can interfere with safe boiler operation |
| Flue and air path | Restricted airflow or recirculation can affect combustion |
| Air-and-gas manifold | Damage, dirt, or incorrect assembly can disrupt the mixture |
| Electrical earth and wiring | Poor connections can affect flame-signal detection |
| Control board | The ignition and flame-monitoring sequence may not be controlled correctly |
Worcester’s service sequence covers these areas, but it is written for trained personnel. It includes electrical measurements, gas-pressure tests, combustion analysis, gas-valve work, internal disassembly, and replacement of safety-critical components.
Can You Continue Using a Boiler Showing EA?
The boiler will normally be unable to provide reliable heating or hot water while the fault remains. Do not try to bypass the lockout or operate the appliance with its casing removed.
One reset may be appropriate after a safe external cause has been addressed, such as restoring the household gas supply or thawing a ground-level condensate pipe. When the fault returns, leave the boiler alone and arrange a professional inspection.
When to Call an Engineer Immediately
Arrange urgent professional help when:
- EA returns after one correct reset.
- No gas-supply or frozen-pipe issue is found.
- The boiler repeatedly clicks without lighting.
- The flame starts and repeatedly cuts out.
- The flue is damaged or appears obstructed.
- The condensate pipe is inaccessible or blocked internally.
- Water is leaking from the appliance.
- The casing, seals, wiring, gas valve, or combustion components need inspection.
- There is soot, unusual staining, or a carbon-monoxide warning.
- You are uncertain whether the appliance is safe.
In the United Kingdom, gas work must be performed by a business or engineer on the Gas Safe Register and qualified for the relevant appliance. Gas Safe is the official registration body for the UK, Isle of Man, Jersey, and Guernsey.
In the Republic of Ireland, domestic natural-gas and LPG work must be completed by a Registered Gas Installer.
Preventing Another EA Fault
Not every EA fault can be prevented, but these measures can reduce avoidable problems:
- Have the boiler inspected and serviced at the recommended interval.
- Keep the external flue area clear without touching or modifying the terminal.
- Ask an installer about protecting or rerouting external condensate pipework when it freezes repeatedly.
- Do not alter the condensate drain.
- Keep gas-meter credit available where a prepayment meter is used.
- Deal with recurring ignition lockouts instead of relying on resets.
- Keep an audible carbon-monoxide alarm installed and maintained according to its instructions.
Worcester’s newer operating instructions recommend regular inspection and maintenance by an approved contractor and advise immediate correction of heating-system defects.
Frequently Asked Questions
Is the Worcester Bosch EA code always caused by a frozen condensate pipe?
No. A frozen condensate pipe is one recognised cause, especially during prolonged cold weather, but EA can also result from a gas-supply problem, blocked flue, ignition fault, flame-detection issue, gas valve problem, wiring fault, or combustion problem.
What does EA 227 mean on a Worcester boiler?
Some Worcester control systems show EA with a numerical subcode. It generally relates to the boiler failing to establish or confirm a flame during the ignition sequence. Because code wording varies between model families, record the complete display and check the manual for the exact appliance.
Can I reset the boiler more than once?
Avoid repeated resets. One reset may be reasonable after checking for a clear external problem. When EA returns, repeated ignition attempts do not repair the cause and may delay necessary professional diagnosis.
Why does my boiler show EA even though the gas hob works?
A working hob suggests that gas is reaching the property, but it does not confirm that the boiler is receiving the correct pressure or that its gas valve, ignition system, flame detection, flue, and combustion components are working correctly. Further testing requires a registered engineer.
Can low boiler pressure cause EA?
EA specifically concerns flame detection. Low water pressure usually produces different symptoms or codes, although the boiler’s general operating condition should still be checked according to its manual. Do not assume that repressurising will clear an EA ignition fault.
How long should I hold the Worcester reset button?
It depends on the model. Greenstar CDi Classic instructions specify about three seconds, while Greenstar i System instructions specify approximately five seconds. Ri models may use a reset position on the heating-temperature knob, and newer 8000 controls use an on-screen reset option.
Can I remove the boiler cover to check the electrode?
No. A casing secured by screws may form part of the appliance’s combustion seal. Gas Safe guidance states that an integral casing should not be removed by a consumer or an unregistered person.
Will replacing the ignition electrode clear EA?
Only when testing confirms that the electrode is defective. EA has several possible causes, so replacing parts without diagnosis may not solve the problem.
Oliver Grant is a UK appliance diagnostics writer with 10 years of experience covering washing machines, boilers, dishwashers, and tumble dryers. He specializes in fault-code interpretation, model-specific checks, and clear guidance based on official technical documentation.