BoilerFaultCodesWorcester Bosch Fault 11 / 131 Fault Code
Also written as FAULT11131 — same fault.
The Worcester Bosch Fault 11 / 131 fault code means: your boiler has detected a new internal electronic component or communication device and requires a manual reset to confirm and sync the system.. It appears on 1 Worcester Bosch model in our database.
Technical description: System configuration: new BUS device. New ISM detected.
What causes the Worcester Bosch Fault 11 / 131 fault?
This fault occurs when the boiler's main control board detects a new electronic component or external wireless device trying to communicate with it. It acts as a security handshake, triggered because the system needs manual permission to integrate the new hardware and ensure it is compatible. The most common reason is that a new smart thermostat or internal wireless module has just been installed or replaced.
DIY fix possible
Locate the Reset button on the boiler control panelPress and hold the Reset button for approximately five secondsWait for the boiler to restart and check if the error code has cleared
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Gas Safe Register →Worcester Bosch models that show the Fault 11 / 131 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch Fault 11 / 131 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