How much does it cost to fix Saunier Duval error code Red led permanently on?

Typical repair cost for the Saunier Duval Red led permanently on fault is £80-150 including labour.

Red led permanently on High

Saunier Duval Red led permanently on Fault Code

Q: What does the Saunier Duval Red led permanently on fault code mean?

Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.

Also written as REDLEDPERMANENTLYON — same fault.

The Saunier Duval Red led permanently on fault code means: your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.. It appears on 1 Saunier Duval model in our database.

Technical description: Insufficient water pressure (below 0,5 bar) or low water pressure switch faulty

Typical repair cost £80-150 (including labour)

DIY fix possible

Locate the filling loop, which is usually a flexible silver braided hose with one or two valves located underneath the boiler.Gradually open the valve(s) to allow mains water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close the valve(s) tightly and restart the boiler to clear the fault.

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Saunier Duval models that show the Red led permanently on fault code

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

Semia Condens F30 E Repair: £80-150

Source

Saunier Duval Red led permanently on 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