BoilerFaultCodesVokera E40 Fault Code
The Vokera E40 fault code means: your boiler has detected an issue with the electrical power supply frequency coming into your home.. It appears on 1 Vokera model in our database.
Technical description: 50 Hz error
What causes the Vokera E40 fault?
This fault occurs when the boiler's internal computer detects that the incoming electricity supply is not at the steady 50Hz frequency required for safe operation. The most common reason is an issue with the local power grid or a malfunctioning main control board failing to read the electrical signal correctly. In some cases, it can be triggered by unstable power from an external generator or a faulty uninterruptible power supply (UPS).
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 E40 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera E40 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