F19 High

Saunier Duval F19 Fault Code

The Saunier Duval F19 fault code means: your boiler has lost its connection to the sensor that monitors the flow of water, meaning it cannot confirm that water is circulating properly through your heating system.. 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: Central heating flow sensor unclipped
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 F19 fault code

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

Source

Saunier Duval F19 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 31 August 2026