Worcester Bosch EA 261 fault codewhat it means and how to fix it
An ignition fault that Worcester define two ways: on the Greenstar i it points at the heat control module, on the Compact range it means the flame was not established inside the four-second ignition window.
Stop — this needs an engineer
Get a Gas Safe registered engineer to look at your Worcester Bosch EA 261
We do not pass enquiries to a repair firm, so there is no form here. Find a Gas Safe registered engineer through the Gas Safe Register, and ask to see their registration card when they arrive — it is the register, not the van, that tells you they are qualified.
Which boiler is showing it?
The right answer depends on what you can see. Pick the one that matches.
Choose the option on the left that matches what your appliance is doing, and the answer for that case appears here.
A Greenstar i or i System with the text display
Worcester's reading here is the heat control module. If the code has appeared since a repair, the module may not be fully seated or may be the wrong one for the boiler.
Reset once as the user guide allows. If it returns, call an engineer and mention any recent board or module work.
A CDi Compact, Si Compact or i System Compact
This is an ignition timing failure. The gas is there but the flame is not established fast enough, which usually comes back to gas pressure, condensate or the electrodes.
Check the condensate pipe outside is not frozen, reset once, and if it recurs book a Gas Safe registered engineer.
There is a smell of gas
Repeated ignition attempts release small amounts of gas. A smell means it is not clearing.
Do not reset again. Turn the gas off at the meter, open windows, and call 0800 111 999.
What EA 261 means
EA is Worcester's ignition and ionisation group, and 261 is the cause code within it that means different things on different Greenstars. The Greenstar i ErP table reads "EA 261 — HCM potentially defective — reset the appliance; if it continues to go to this error, check the HCM is inserted properly, check the HCM number, check for blocked condensate pipes, contact technical helpline". The HCM is the heat control module, the small plug-in module that tells the control board which appliance it is running.
The CDi Compact and Si Compact ErP tables give the same pairing as "ignition timing error — flame not established during the first 4 seconds ignition period". The two readings are not as far apart as they sound. On both ranges the board opened the gas valve, sparked, and did not see a stable flame within the time the ignition program allows; the i-series manual simply points first at the module that sets that timing. It sits alongside EA 227, which is the more familiar failure of all ignition attempts, and EA 229, which is a flame lost after it was burning.
Worcester allow the owner a reset and no more. What makes it a danger-rated code is what it is: gas released and not lit, on repeat. If a single reset does not hold, the causes to be checked are the same as any ignition failure — gas pressure, condensate drainage, electrodes and their leads — plus, on the Greenstar i, the module itself.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Heat control module loose or wrong | On the Greenstar i, Worcester's first check is that the HCM is pushed fully home and carries the right number for the appliance. A module disturbed during a board change is the classic case. | Common |
| Flame slow to establish | Low gas pressure, air in the supply after work on the meter, or a gas valve that is slow to open means the flame is not stable inside the four-second window the Compact manuals describe. | Common |
| Blocked condensate trap | Worcester include blocked condensate pipes in the checks for 261. Water backing up into the sump disturbs the burner at the moment of ignition. | Occasional |
| Electrode or lead deterioration | A worn spark electrode or a cracked lead gives a weak spark that lights late or intermittently, so the timing check fails. | Occasional |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£90–£320
Time on site
1h 15m
Reseating or replacing the heat control module £90–£160. Electrodes and leads £130–£220. Gas valve £300–£480 if that is what is slow to open.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Parts you may need
We may earn a commission if you buy a part through one of these links. It does not change what you pay, and it does not affect which parts we list.
Worcester Bosch Greenstar electrode set
87161431020£22–£52Authorised Worcester parts distributor
Price checked 28 September 2026
Worcester Bosch Greenstar spark generator
8716117077£40–£90Authorised Worcester parts distributor
Price checked 28 September 2026
Worcester Bosch Greenstar heat control module (HCM) or code plug
£30–£90Authorised Worcester parts distributor
Price checked 28 September 2026
Own this appliance and had this code? . Nothing is published until a person has read it.
Related Worcester Bosch fault codes
- EA 227Stop — call an engineerThe boiler tried to light and never detected a flame, so it has shut the gas off and locked out. This is the most common Worcester fault code.Related: ignition and gas supply
- EA 229Get it checkedThe burner lit and then the flame was lost during operation. That is a different fault from failing to light in the first place.Related: ignition and gas supply
- F7 228Stop — call an engineerA flame is being detected before the burner has started. Switch the appliance off and get a Gas Safe engineer rather than resetting.Related: ignition and gas supply
- FA 306Stop — call an engineerThe boiler detected a flame after it had closed the gas valve. That points to a valve letting gas past when it should be shut, and it must not be reset.Related: ignition and gas supply
- 2951Stop — call an engineerThe flame has been lost too many times in a row and the boiler has locked out. Each loss was a 229; Worcester's instruction is to read the history and find what put it out.Related: ignition and gas supply
- EA 234Get it checkedThe control board cannot see the gas valve coil, so it will not attempt to light. Worcester call it a gas valve error, coil disconnected. No gas is released, but it is a gas job.Related: ignition and gas supply
Own a Worcester Bosch boiler? Save it and its codes come first next time.
Related guides
Common questions about Worcester Bosch EA 261
What is the HCM?
The heat control module — Worcester's name for the plug-in identification module on the Greenstar i control board. It carries the appliance's identity and settings. If it is loose, missing or the wrong part, the board cannot run the ignition sequence correctly, and Worcester's 9U 233 code is the more direct report of that.
How is 261 different from EA 227?
227 is the report that every ignition attempt failed and no flame was ever detected. 261 is narrower: the sequence did not establish a flame inside the timed window. On the Compact range they can have identical causes; on the Greenstar i, 261 points first at the module.
Can I keep pressing reset?
Once. Worcester's user guide describes a single brief press and says some codes cannot be cleared by a simple reset. An ignition fault that survives one reset needs an engineer, not a third attempt.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.