BoilerFaultCodesWorcester Bosch 2/3/1 Fault Code
Also written as 231 — same fault.
The Worcester Bosch 2/3/1 fault code means: your boiler has experienced a power cut while it was already trying to recover from a serious internal safety fault, meaning it is currently unable to restart safely.. It appears on 1 Worcester Bosch model in our database.
Technical description: The power supply was interrupted during a locking fault 4A, 4C, 4E, 4F, 4L, 4P, 4U, 4Y.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Worcester Bosch models that show the 2/3/1 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 2/3/1 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 7 July 2026