BoilerFaultCodesWorcester Bosch 242 Fault Code
The Worcester Bosch 242 fault code means: your boiler has experienced an internal electrical error that is preventing it from firing up to provide heating or hot water.. It appears on 7 Worcester Bosch models in our database.
Technical description: Boiler electr. system fault
What causes the Worcester Bosch 242 fault?
This fault occurs when the boiler's control system detects an inconsistency in the electrical signals required to manage the burner safely. It is usually caused by a failure in the ignition components or a breakdown in the communication between the sensors and the main control board. If the boiler cannot confirm a safe flame is present, it will stop working as a safety precaution.
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 242 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 242 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
- Worcester Bosch 24/28/35 CDi MkII manual (PDF)
- Worcester Bosch Greenstar 2000 manual (PDF)
- Worcester Bosch Greenstar 27CDi manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026