BoilerFaultCodesVokera E12 Fault Code
The Vokera E12 fault code means: your boiler has become too hot and has shut itself down for safety to prevent damage.. It appears on 1 Vokera model in our database.
Technical description: Appliance overheat
What causes the Vokera E12 fault?
This fault occurs when the water inside the boiler exceeds a safe temperature limit, causing the system to shut down to prevent internal damage. The most common reasons are a pump failure that stops water from moving or a blockage in the heat exchanger that restricts flow. It can also be triggered by a build-up of air or sludge within the pipework that prevents heat from being carried away from the burner.
This issue often appears when the heating is first turned on after summer, as the internal pump can seize up after long periods of inactivity.
DIY fix possible
Check that all radiator valves are fully openEnsure the system pressure is between 1 and 1.5 barPress the 'Reset' button on the control panelWait 20 minutes for the unit to cool down before trying to restart
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Vokera models that show the E12 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera E12 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 7 July 2026