BoilerFaultCodesWorcester Bosch F0239 Fault Code
The Worcester Bosch F0239 fault code means: your boiler's internal computer has encountered a critical communication error and cannot safely operate your heating or hot water.. It appears on 2 Worcester Bosch models in our database.
Technical description: Control box or the heat control module (HCM) is defective – the control box connections need checking
What causes the Worcester Bosch F0239 fault?
This fault occurs when the boiler's main brain loses the ability to talk to its internal memory chip, which contains the specific settings for your appliance. The most common reason is a physical failure of the electronic circuits or a loose connection between the internal control modules that prevents the boiler from identifying itself. Because the boiler no longer knows its own safety parameters, it shuts down completely as a protective measure.
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 F0239 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch F0239 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