BoilerFaultCodesWorcester Bosch 8.A Fault Code
Also written as 8A — same fault.
The Worcester Bosch 8.A fault code means: your boiler's internal computer has lost its identity because the memory chip is either loose or failing.. It appears on 1 Worcester Bosch model in our database.
Technical description: Software version CF
What causes the Worcester Bosch 8.A fault?
This fault occurs when the boiler's main control board loses communication with a small memory chip called a code plug, which tells the boiler exactly which model it is. The most common reason is that the chip has vibrated loose over time or its electronic circuits have failed, meaning the boiler can no longer operate safely without knowing its own identity.
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 8.A fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 8.A 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