Boiler displays F10 and shuts down, often associated with low system pressure

Safety first: Allow the system to cool before repressurising to avoid burns.

User-level steps:

• Check the pressure gauge on the boiler. If below 1.0 bar (cold), repressurise using the filling loop according to the Saunier Duval user manual.
• Close the filling loop valves once pressure reaches 1.2–1.5 bar.
• Reset the boiler and check if F10 clears.

If pressure drops again:

• Inspect visible pipework, radiators, and radiator valves for leaks.
• Check the boiler's safety valve discharge pipe outside for dripping (could indicate expansion vessel issues).
• If the gauge shows correct pressure but F10 persists, the pressure sensor may be faulty and require replacement.

Warning: Do not overfill above 2.0 bar. If you cannot maintain pressure, contact a heating engineer to locate leaks or check the expansion vessel.