How much does it cost to fix Ideal error code 12?

Typical repair cost for the Ideal 12 fault is £150-250 including labour.

12 High

Ideal 12 Fault Code

Q: What does the Ideal 12 fault code mean?

Your boiler has detected that either the water pressure inside the system is too low or a safety sensor in the exhaust vent has triggered.

The Ideal 12 fault code means: your boiler has detected that either the water pressure inside the system is too low or a safety sensor in the exhaust vent has triggered.. It appears on 1 Ideal model in our database.

Technical description: Water pressure switch or flue thermostat failure

Typical repair cost £150-250 (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 12 fault code

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

Response SE Repair: £150-250

Source

Ideal 12 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