How much does it cost to fix Saunier Duval error code 24?

Typical repair cost for the Saunier Duval 24 fault is £120-200 including labour.

24 High

Saunier Duval 24 Fault Code

Q: What does the Saunier Duval 24 fault code mean?

Your boiler's temperature sensors have been swapped during installation or maintenance, causing the system to become confused about which way the water is flowing.

The Saunier Duval 24 fault code means: your boiler's temperature sensors have been swapped during installation or maintenance, causing the system to become confused about which way the water is flowing.. It appears on 4 Saunier Duval models in our database.

Technical description: The heating flow thermistor and heating return thermistor are connected the wrong way round.

Typical repair cost £120-200 (including labour)

Engineer required

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

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Saunier Duval models that show the 24 fault code

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

Source

Saunier Duval 24 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