BoilerFaultCodesVokera E18 Fault Code
The Vokera E18 fault code means: your boiler has shut itself down for safety because a internal limit was exceeded, likely due to overheating or a lack of water circulation.. It appears on 2 Vokera models in our database.
Technical description: NTC1 short-circuited (NTC1 = outlet sensor) Probe manifold short-circuited
What causes the Vokera E18 fault?
This fault occurs when the boiler's internal temperature rises too quickly or exceeds a safe limit, causing the system to shut down to prevent damage. The most common reasons are a pump failure that stops water from moving or a buildup of debris and sludge that creates a blockage within the heat exchanger. This lack of circulation means the heat produced by the burner has nowhere to go, triggering the safety sensors.
This issue often appears when the heating is first turned on after summer, as pump components can seize up during long periods of inactivity.
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 E18 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera E18 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