BoilerFaultCodesWorcester Bosch F1263 Fault Code
The Worcester Bosch F1263 fault code means: your boiler's internal computer has developed a fault and can no longer communicate with the main control system, meaning it 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 – HCM or control box connections need to be checked
What causes the Worcester Bosch F1263 fault?
This fault occurs when the boiler's internal computer chips lose the ability to speak to each other, often due to a hardware failure on the circuit board or a loose internal wiring connection. The most common reason is that the Heat Control Module, a small plug-in component that stores the boiler's identity, has worn out or become corrupted over time.
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 F1263 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch F1263 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