E23 High

Vokera E23 Fault Code

The Vokera E23 fault code means: your boiler has shut itself down as a safety precaution because it has detected an internal fault that could lead to overheating or unsafe operation.. It appears on 1 Vokera model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: REFHI TOO LOW ERROR Temperature measured not correct

What causes the Vokera E23 fault?

This fault occurs when the boiler's internal temperature exceeds safe limits, triggering a safety shutdown to prevent damage. The most common reasons are a failure in the pump preventing water from moving through the system, or a faulty sensor incorrectly reporting an overheat. It can also be caused by a blockage in the heat exchanger or air trapped within the unit.

Typical repair cost £120-350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Vokera models that show the E23 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Vokera E23 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