How much does it cost to fix Ideal error code 431?

Typical repair cost for the Ideal 431 fault is £90-160 including labour.

431 High

Ideal 431 Fault Code

Q: What does the Ideal 431 fault code mean?

Your boiler has detected a fault with its temperature sensor, which means the system cannot safely monitor the heat of the water and has stopped working as a precaution.

The Ideal 431 fault code means: your boiler has detected a fault with its temperature sensor, which means the system cannot safely monitor the heat of the water and has stopped working as a precaution.. It appears on 2 Ideal models in our database.

Technical description: NTC1 short circuit

What causes the Ideal 431 fault?

This fault occurs when the boiler's main internal temperature sensor develops an electrical short, preventing it from reading how hot the water is. The most common reason is that the sensor itself has failed internally, or moisture has compromised the electrical connections between the sensor and the main control board.

Typical repair cost £90-160 (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 431 fault code

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

Source

Ideal 431 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