How much does it cost to fix Ideal error code 018?

Typical repair cost for the Ideal 018 fault is £120-250 including labour.

018 High

Ideal 018 Fault Code

Q: What does the Ideal 018 fault code mean?

Your boiler has detected that the water inside the heating system is getting too hot and has automatically shut down to prevent damage.

The Ideal 018 fault code means: your boiler has detected that the water inside the heating system is getting too hot and has automatically shut down to prevent damage.. It appears on 1 Ideal model in our database.

Technical description: Flow temperature T1 too high

Typical repair cost £120-250 (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 018 fault code

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

Maximiser SE Repair: £120-250

Source

Ideal 018 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