F18 High

Saunier Duval F18 Fault Code

The Saunier Duval F18 fault code means: your boiler's control panel and the internal computer are having trouble communicating with each other, meaning the display may not work or respond to your commands.. It appears on 3 Saunier Duval models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: User interface fault. Faulty user interface

What causes the Saunier Duval F18 fault?

This fault occurs when the data link between the display panel you interact with and the main computer inside the boiler is broken. The most common reason is an electronic component failure on one of the circuit boards or a loose connection in the internal wiring harness.

Typical repair cost £180-450 (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 F18 fault code

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

Source

Saunier Duval F18 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