BoilerFaultCodesVokera E04 Fault Code
The Vokera E04 fault code means: your boiler has shut down to protect itself because a safety sensor has detected a fault with the burner or the ignition process.. It appears on 6 Vokera models in our database.
Technical description: Water differential pressure switch (insufficient water or circulation)
What causes the Vokera E04 fault?
This fault occurs when the boiler's control system fails to detect a steady flame after several attempts to light. The most common reasons are a buildup of carbon on the ignition parts, an inconsistent fuel supply, or a sensor that has become too dirty to 'see' the flame. It functions as a safety shutdown to ensure gas does not flow without being safely burned.
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 E04 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera E04 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