An “EA” fault code on a Worcester Bosch boiler, accompanied by a flashing blue light, indicates a flame detection error. This means the boiler is unable to detect the flame required to heat water for central heating or hot water. According to the Worcester Bosch manual, this error signifies that the flame has not been detected.
If the boiler displays an EA fault code with a flashing red light, it also indicates a flame detection error, often suggesting a more critical issue: The boiler’s Printed Circuit Board (PCB) cannot confirm that a flame has ignited after four ignition attempts. To protect the boiler’s components and reduce external risks, the PCB locks the boiler out.
No gas supply to the boiler
Low gas pressure
Faulty gas valve
Blocked flue
Blocked condensate pipe or condensate trap
Faulty ignition electrodes or lead
Issue with the flame sensor
Flue gas sensor issue (applicable to specific models)
Faulty fan
PCB (Printed Circuit Board) fault
Check the gas meter to ensure the gas supply is active and uninterrupted.
Verify gas pressure at the meter and ensure it meets the required levels. If the pressure is too low, the boiler will fail to ignite.
A defective gas valve can prevent the boiler from receiving adequate gas for ignition. If confirmed, it must be replaced.
Inspect the flue for blockages, such as debris or obstructions. Clear them, ensuring the flue is safe, with no holes or corrosion.
A blockage in the condensate pipe or condensate trap can lead to a fault. Unblock the pipe and the condensate trap, ensuring proper drainage.
Worn-out or damaged ignition electrodes can fail to spark a flame. Replace the electrodes or leads as necessary.
The flame sensor (part of the ignition electrode assembly) detects the flame during operation. If faulty, it needs replacing.
On some models, a faulty flue gas sensor can cause an EA fault. Replace the sensor if required.
A faulty fan can prevent the boiler from venting exhaust gases safely, causing a lockout. If the fan stops working due to a blocked condensate pipe, a C6 fault code may also appear alongside the EA fault. Replace the fan if necessary.
The PCB, responsible for managing all operations, might need replacement. This is often the most expensive component to repair or replace. In some cases, replacing the boiler may be more cost-effective.
The Printed Circuit Board (PCB) acts as the boiler’s control centre, managing every stage of its operation. When an EA fault occurs, it means the PCB has attempted ignition four times but has failed to detect a flame. To safeguard the system, the PCB initiates a lockout, preventing further attempts to ignite.
If a PCB fault is diagnosed, it must be replaced. However, given the high cost of this component, replacing the entire boiler may sometimes be a more practical and economical solution.
While minor issues, such as clearing a blocked condensate pipe or flue, low gas pressure at meter, can often be resolved without parts, complex problems, such as gas valve or PCB faults, require costly replacement parts. It is often more economical and a better investment to replace the boiler, giving you peace of mind as new boilers are supplied with an extended 10 or 12-year manufacturer parts and labour warranty.
Always consult a Gas Safe registered engineer for diagnostics and repairs to ensure your boiler operates safely and efficiently.
Understanding the causes and solutions for an EA fault code can help restore your Worcester Bosch boiler to full functionality with minimal disruption.
20th August, 2026
18th March, 2026
