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

Typical repair cost for the Chaffoteaux 12 fault is £90-160 including labour.

12 High

Chaffoteaux 12 Fault Code

Q: What does the Chaffoteaux 12 fault code mean?

Your boiler's internal thermometer for the heating system has stopped working, meaning the unit cannot safely tell how hot the water is and has shut down as a precaution.

The Chaffoteaux 12 fault code means: your boiler's internal thermometer for the heating system has stopped working, meaning the unit cannot safely tell how hot the water is and has shut down as a precaution.. It appears on 9 Chaffoteaux models in our database.

Technical description: Central Heating thermistor faulty (open circuit)

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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Chaffoteaux models that show the 12 fault code

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

Source

Chaffoteaux 12 fault code information on this page is sourced and cross-checked against the official Chaffoteaux service / installation manuals for each affected model.

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