Does fan run? (NO) High

Saunier Duval Does fan run? (NO) Fault Code

Also written as DOESFANRUNNO — same fault.

The Saunier Duval Does fan run? (NO) fault code means: your boiler is failing to start because the internal air extraction fan, which is essential for safe operation, is not receiving power or has stopped working.. It appears on 2 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: Is there 230V~ between motor connections on fan? If YES, replace fan. If NO, isolate electrical supply and test fan harness continuity. If satisfactory replace printed circuit board.
Typical repair cost £200-£400 (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 Does fan run? (NO) fault code

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

Source

Saunier Duval Does fan run? (NO) 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