BoilerFaultCodesWorcester Bosch F0242 Fault Code
The Worcester Bosch F0242 fault code means: your boiler's internal computer has encountered a critical communication error and cannot operate safely.. It appears on 1 Worcester Bosch model in our database.
Technical description: Control box or the heat control module (HCM) is defective – the HCM and control box connections need to be checked
What causes the Worcester Bosch F0242 fault?
This fault occurs when the boiler's internal computer brain loses its connection with the specific data chip that holds its operating instructions. It is usually caused by a physical failure of the Heat Control Module chip or a breakdown in the electrical circuits on the main control board. Because the boiler no longer knows its own safety limits, it shuts down immediately to prevent damage.
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 F0242 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch F0242 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