BoilerFaultCodesVokera E12 Fault Code
The Vokera E12 fault code means: your boiler has shut itself down as a safety precaution because it has detected an internal fault or overheating.. It appears on 2 Vokera models in our database.
Technical description: Low temperature zone room thermostat intervention
What causes the Vokera E12 fault?
This fault occurs when the boiler's internal safety sensors detect that the system is getting too hot or that water isn't moving through the unit correctly. It is often triggered by a circulation issue, such as a failing pump or a blockage, which causes the heat exchanger to reach a dangerous temperature. To prevent any damage, the boiler automatically shuts down and locks itself for your safety.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →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 27 April 2026