BoilerFaultCodesWorcester Bosch 1-EA Fault Code
Also written as 1EA — same fault.
The Worcester Bosch 1-EA fault code means: your boiler's internal computer has identified a mismatch or issue with its software version, which prevents it from operating correctly.. It appears on 3 Worcester Bosch models in our database.
Technical description: Software version of the equipment electronics (main version)
What causes the Worcester Bosch 1-EA fault?
This fault occurs when there is a communication failure or a data mismatch between the boiler's main control board and its memory chip, known as the code plug. It usually happens if the electronics have suffered a software corruption or if the internal components are no longer compatible with one another. Essentially, the boiler’s 'brain' no longer recognises its own operating instructions and shuts down for safety.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Worcester Bosch models that show the 1-EA fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 1-EA fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026