How much does it cost to fix Ideal error code E18?

Typical repair cost for the Ideal E18 fault is £150-300 including labour.

E18 High

Ideal E18 Fault Code

Q: What does the Ideal E18 fault code mean?

Your boiler has automatically shut down because it has detected that its internal temperature has risen to an unsafe level.

The Ideal E18 fault code means: your boiler has automatically shut down because it has detected that its internal temperature has risen to an unsafe level.. It appears on 1 Ideal model in our database.

Technical description: Boiler overheat thermostat: Boiler overheating is detected by electrical sensors connected to the boiler control module.

Typical repair cost £150-300 (including labour)

Engineer required

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

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Ideal models that show the E18 fault code

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

Imax W Repair: £150-300

Source

Ideal E18 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026