BoilerFaultCodesVokera 78 Fault Code
The Vokera 78 fault code means: your boiler has detected a temporary internal communication error or a sensor synchronization issue that is preventing it from running properly.. It appears on 3 Vokera models in our database.
Technical description: Temporary fault code (Refer to section 7.10)
What causes the Vokera 78 fault?
This fault occurs when the boiler's internal control board loses track of the temperature readings because the signals from the sensors are inconsistent or mismatched. It is often caused by a failing hot water sensor sending incorrect data or a minor electronic glitch on the main circuit board that prevents the components from communicating correctly.
DIY fix possible
Turn the selector switch to the 'OFF/RESET' position.Wait for approximately 30 seconds.Turn the selector switch back to the 'ON' position (Heating and Hot Water icon).
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Gas Safe Register →Vokera models that show the 78 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera 78 fault code information on this page is sourced and cross-checked against the official Vokera service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026