BoilerFaultCodesWorcester Bosch E5 Fault Code
The Worcester Bosch E5 fault code means: your boiler has encountered an internal electronic communication error that is preventing it from running safely.. It appears on 8 Worcester Bosch models in our database.
Technical description: Flow temperature too high. Primary sensor overheated.
What causes the Worcester Bosch E5 fault?
This fault occurs when the boiler's internal computer brain fails to communicate properly with the other sensors and components inside the unit. It is usually caused by a physical failure of the main circuit board or a loose connection in the internal wiring harness that prevents data from traveling through the system. Because the boiler cannot verify that it is operating safely, it stops running as a protective measure.
DIY fix possible
Press the 'Reset' button on the control panel once.Wait up to 15 minutes for the boiler to restart.If the code persists, do not attempt further repairs and contact a Gas Safe engineer.
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Gas Safe Register →Worcester Bosch models that show the E5 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch E5 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