Worcester Bosch EA Fault Code: Flame Not Detected Guide
The EA fault code is one of the most common Worcester Bosch boiler faults. It means the boiler could not detect a flame, or the flame has gone out during operation.
What the EA fault code means
The EA code is a flame not detected / gone out fault. The boiler attempted to ignite the burner, but either no flame was established or the flame was detected and then lost. This triggers a full combustion trail diagnosis.
Possible causes of the EA fault
A full combustion trail is needed to diagnose this fault. The possible causes include:
- Gas supply pressure — The gas may not be reaching the boiler at the correct pressure.
- Power supply — The boiler may not be receiving the correct electrical supply.
- Condensate outlet blocked or frozen — A blocked condensate pipe can prevent the boiler from igniting.
- Igniter lead and electrodes — The ignition system may be worn or faulty.
- Ionisation electrode — The flame sensing electrode may not be detecting the flame correctly.
- Flue blockage — The flue may be blocked or restricted.
- Bearing plate blockage — Internal blockage in the boiler.
- Flue duct integrity — The flue system may be damaged or incorrectly installed.
- CO2 levels — The combustion may be out of adjustment.
Can you fix it yourself?
There are a few things you can check before calling an engineer:
-
Check your gas supply — Make sure other gas appliances are working. If they aren't, the issue is with your gas supply, not the boiler.
-
Check for a frozen condensate pipe — In cold weather, the condensate pipe that runs outside can freeze and block. If you can safely access the pipe, pour warm (not boiling) water over it to thaw any ice.
-
Check the flue terminal — Make sure the flue terminal outside is not blocked by debris, snow, or vegetation.
-
Reset the boiler — After checking the above, try resetting the boiler. On most Worcester Bosch Greenstar boilers, press and hold the reset button for 3–5 seconds.
If the EA code returns after resetting, the cause is likely a faulty electrode, blocked condensate, flue issue, or combustion adjustment problem. This needs a Gas Safe registered engineer.
When to call a professional
If you've checked your gas supply, ruled out a frozen condensate pipe, checked the flue terminal, and the EA fault persists, call a Gas Safe registered engineer. The engineer will need to carry out a full combustion trail, which includes:
- Testing gas supply pressure
- Checking the igniter lead and electrodes
- Inspecting the ionisation sensing electrode
- Checking the flue for blockages and integrity
- Measuring CO2 levels and adjusting combustion
Need help with your Worcester Bosch boiler?
Sanju's Heating covers Newbury, Basingstoke and Reading. We're Gas Safe registered and can diagnose and repair Worcester Bosch EA faults quickly with transparent pricing.
Call us on 01635 74 50 40 or book online at sanjusheating.co.uk/book
Check our full Worcester Bosch fault code guide for help with other Worcester error codes.
