The EA code on a Worcester Bosch gas boiler means the boiler tried to light but could not detect a flame, so it has locked out to keep you safe. This guide explains the Worcester Bosch EA error code, including the EA 227 and EA 229 versions, what you can safely check yourself and when a Gas Safe registered engineer has to take over.
Quick answer: EA means flame not detected. Worcester Bosch says to check that the gas is on, the condensate pipe is not frozen and the flue outlet is not blocked. You can thaw a frozen condensate pipe with warm water and reset the boiler. If EA returns, stop and call a Gas Safe registered engineer.
What Does the Worcester Bosch EA Error Code Mean?
EA is a lockout fault that means the boiler has not detected a flame at the burner. The Worcester Bosch Greenstar CDi Classic user instructions list EA as “flame not detected” and ask the user, if it is safe to do so, to check that the gas is on in the house, that the condensate pipe is not frozen and that the flue outlet is not blocked.
Every time a gas boiler lights, a sensing electrode confirms that gas is actually burning. If that confirmation does not arrive, the control board shuts the gas valve and shows a fault rather than keep releasing unburnt gas. On older Greenstar models with a two character display you will usually see EA on its own with a flashing reset button. Newer Greenstar models with a text display, such as the Greenstar 4000, show the fault as text with a three digit fault number.
EA 227 and EA 229: what is the difference?
Independent heating references describe EA 227 as no flame detected after the ignition attempts, meaning the burner never lit properly. They describe EA 229 as a flame that lit but was then lost while the boiler was running. Both point to the same family of problems: gas supply, condensate drainage, flue, or the ignition and flame sensing parts. The exact wording can differ between Greenstar ranges, so check your model’s manual for the description that applies to your boiler.
What Causes the EA Error?
The causes below run roughly from the most common, which a homeowner can check, to the ones that need an engineer.
- Frozen or blocked condensate pipe. Worcester Bosch says a blocked condensate pipe can cause an EA code, often with a gurgling sound from the boiler, and it is most likely when part of the pipe runs outside in a long cold spell.
- No gas reaching the boiler. A prepayment meter that has run out of credit, a gas supply interruption in the street or a closed valve will all stop the burner lighting.
- Blocked flue outlet. Leaves, nests or snow around the terminal outside can starve the burner of air or stop combustion gases leaving.
- Worn, dirty or misaligned ignition or flame sensing electrode. The flame may light but not be detected.
- Gas valve, wiring or control board fault. Less common, and only a Gas Safe engineer can test these parts.
How Do You Fix the EA Error Yourself?
Work through these checks in order. They are limited to what the Worcester Bosch user instructions allow a homeowner to do, and none of them involve removing the boiler casing.
- Check the gas is on. Try another gas appliance such as the hob. If nothing works, check prepayment credit and contact your supplier or the gas emergency service if you suspect a supply problem. If you smell gas, open doors and windows, turn the gas off at the meter control valve if you know where it is, and call the gas emergency number, 0800 111 999.
- Look at the condensate pipe. It is usually a white plastic pipe running from the boiler to an outside drain. Ice, a frosty section or a pipe that feels solid near a bend or the open end are signs of a freeze.
- Thaw it with warm water, never boiling. Worcester Bosch advises a hot water bottle, a microwaveable heat pack or a cloth soaked in hot water held against the pipe near the blockage, or warm water poured along it from a watering can. Only thaw a pipe that is at ground level and easy to reach, and mop up any water on paths so it does not freeze.
- Check the flue terminal from the ground. Look for an obvious blockage such as leaves or a nest. Do not climb up to it or poke anything into it; a blocked flue is a job for an engineer.
- Check the pressure gauge. Worcester Bosch suggests about 1 to 1.5 bar when the system is cool. If it is below 1 bar, top up through the filling loop as your manual describes.
- Reset the boiler once. On older models such as the Greenstar CDi Classic, hold the reset button for about 5 seconds after thawing and wait 2 to 3 minutes for the boiler to restart. On models with a text display, such as the Greenstar 4000, use the arrow keys until Reset appears.
Safety: Stop here. If EA comes back after one reset, or you smell gas, see scorch marks or hear unusual banging, do not keep resetting and never remove the boiler casing. Electrodes, gas valves, flues and wiring must only be checked by a Gas Safe registered engineer.
When Should You Call an Engineer?
Call a Gas Safe registered engineer if EA returns after you have confirmed gas is reaching the house, thawed the condensate pipe and reset the boiler once. Call one straight away if the condensate pipe is high up, if the flue looks blocked or damaged, or if the boiler has been showing EA repeatedly over several days. Worcester Bosch’s own advice is to contact your installer or its customer service and give them the fault code shown.
Before the visit, note the full code on the display (for example EA 227 or EA 229), when it first appeared, what you have already tried and whether other gas appliances work. The HSE domestic gas guidance says anyone working on gas appliances in a home must be Gas Safe registered, so ask to see the engineer’s ID card and check it on the Gas Safe Register. If the boiler is still under a Worcester Bosch guarantee, read the guarantee terms before booking anyone.
We have not given a repair price because Worcester Bosch does not publish one and costs depend on the part, your region and your guarantee. If the boiler is old and faults keep returning, our boiler size calculator helps you see what output a replacement would need.
Worcester Bosch EA and Related Codes
The codes below come from the Greenstar CDi Classic user instructions unless marked. Meanings can vary between ranges, so check the manual for your model.
| Code | Meaning | Who deals with it |
|---|---|---|
| EA | Flame not detected | You: gas on, condensate pipe, flue view, one reset. Then engineer |
| EA 227 (newer models) | No flame detected after ignition (independent sources) | As EA |
| EA 229 (newer models) | Flame lost during operation (independent sources) | As EA |
| C6 | Fan speed too low | Gas Safe engineer |
| E9 | Safety temperature limiter in the heating flow has tripped | Gas Safe engineer |
| E2 | Heating flow temperature sensor defective | Gas Safe engineer |
| A7 | Hot water temperature sensor defective | Gas Safe engineer |
| FA | Flame detected after gas shut off | Gas Safe engineer |
| Fd | Reset button pressed by mistake | You: reset as your manual describes |
How Can You Stop the EA Error Coming Back?
Most repeat EA faults in winter come from the condensate pipe, so that is the first thing to protect. Worcester Bosch’s installer guidance links poorly sized or uninsulated external condensate pipework to EA faults, and recommends that external runs are kept to 3 m at most, using 32 mm pipe, and insulated where the boiler model requires it. Ask a heating engineer to check yours if it freezes more than once.
- Have the boiler serviced every year by a Gas Safe registered engineer, who will inspect the electrodes, burner and flue.
- Keep the flue terminal outside clear of plants, bins and stored items.
- Keep a prepayment meter topped up in cold weather, when the boiler uses the most gas. Our gas bill calculator shows how winter use adds up.
- Check the pressure gauge once a month and keep it in the range your manual gives.
For more heating tools, including radiator and heat pump sizing, see our heating calculators.
Worcester Bosch EA Error Code FAQs
Can I reset a Worcester Bosch boiler showing EA?
Yes, a reset is allowed once you have checked the gas supply, the condensate pipe and the flue outlet. Hold the reset button or use the display menu as your manual describes. If EA returns after one reset, stop and call a Gas Safe registered engineer.
Is the EA code dangerous?
The code itself is a safety feature: the boiler has shut off the gas because it could not confirm a flame. Leaving the boiler locked out is the safe state. If you smell gas, open the windows, turn off the gas at the meter if you can and call 0800 111 999.
Why does my Worcester boiler show EA in cold weather?
In cold weather the most likely cause is a frozen condensate pipe. Worcester Bosch says a blocked condensate pipe can trigger EA, often with a gurgling noise. Thaw a ground level pipe with warm, not boiling, water and then reset the boiler.
What is the difference between EA 227 and EA 229?
Independent references describe EA 227 as no flame detected after ignition, and EA 229 as a flame that was lost while the boiler was running. Both lock the boiler out. Check your model’s manual for the exact wording on your boiler.
Can low boiler pressure cause the EA code?
Low pressure is not listed by Worcester Bosch as a cause of EA, but it is still worth checking while you look. Worcester Bosch suggests around 1 to 1.5 bar when the system is cool. Top up through the filling loop if it is below 1 bar.
Will I still have hot water with an EA fault?
No, not from the boiler. EA is a lockout, so the burner will not light for heating or hot water until the cause is fixed and the boiler is reset. An electric shower or immersion heater, if you have one, will still work.
Checked October 2026. Sources: Worcester Bosch Greenstar CDi Classic combi user instructions, Worcester Bosch Greenstar 4000 user instructions, Worcester Bosch: Handy advice for efficient heating this winter, Worcester Bosch: Frozen condensate useful information, Worcester Bosch: external condensate pipe FAQ, HSE domestic gas FAQs, Gas Safe Register.
