How much does it cost to fix Saunier Duval error code 31.?

Typical repair cost for the Saunier Duval 31. fault is £120-220 including labour.

31. High

Saunier Duval 31. Fault Code

Q: What does the Saunier Duval 31. fault code mean?

Your boiler has detected an electrical fault with one of its temperature sensors, meaning it cannot accurately measure the heat inside the system and has stopped working as a safety precaution.

Also written as 31 — same fault.

The Saunier Duval 31. fault code means: your boiler has detected an electrical fault with one of its temperature sensors, meaning it cannot accurately measure the heat inside the system and has stopped working as a safety precaution.. It appears on 4 Saunier Duval models in our database.

Technical description: The heating flow thermistor is short circuited.

Typical repair cost £120-220 (including labour)

Engineer required

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

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Saunier Duval models that show the 31. fault code

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

Source

Saunier Duval 31. fault code information on this page is sourced and cross-checked against the official Saunier Duval service / installation manuals for each affected model.

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