How much does it cost to fix Vokera error code E 18?

Typical repair cost for the Vokera E 18 fault is £150-250 including labour.

E 18 High

Vokera E 18 Fault Code

Q: What does the Vokera E 18 fault code mean?

Your boiler has detected that the water temperature has risen too high and has safely shut itself down to prevent damage.

Also written as E18 — same fault.

The Vokera E 18 fault code means: your boiler has detected that the water temperature has risen too high and has safely shut itself down to prevent damage.. It appears on 1 Vokera model in our database.

Technical description: Flow sensor temperature exceeded

What causes the Vokera E 18 fault?

This fault occurs when the water leaving the boiler gets too hot too quickly, causing the system to shut down for safety. The most common reasons are a pump failure that stops water from moving or a blockage like sludge or trapped air preventing flow through the heat exchanger.

This issue is more common when the heating is first turned on after summer, as the internal pump can seize up after long periods of inactivity.

Typical repair cost £150-250 (including labour)

DIY fix possible

Check that all radiator valves are fully openEnsure the boiler pressure gauge is between 1.0 and 1.5 barSwitch the boiler off and on again to see if the fault clears after cooling

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Vokera models that show the E 18 fault code

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

Hydra Repair: £150-250

Source

Vokera E 18 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