BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Locate the external filling loop, which is usually a flexible silver hose connected between two pipes under your boiler.Open the valves at both ends of the hose to allow mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close both valves tightly and remove the hose if required by your specific model.
Your boiler has lost its electrical power supply, which could be due to a power cut in your home or a tripped fuse.
Check your home's fuse box or consumer unit to see if the boiler's circuit breaker has tripped.Ensure the boiler's fused spur switch, usually located on the wall nearby, is turned on.If the power is on, try turning the boiler off at the isolation switch, waiting 30 seconds, and turning it back on to reset the system.
Your boiler has detected that waste water cannot drain away properly, likely due to a blockage or frozen external pipe, causing it to shut down for safety.
Locate the plastic pipe exiting your property wall specifically for the boiler condensation.If it is freezing outside, carefully pour warm (not boiling) water over the pipe to thaw any potential ice blockages.Once the pipe is clear, reset your boiler to see if the fault code clears.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.
Locate the filling loop (usually a silver braided hose with one or two valves) under your boiler.Gradually open the valve(s) to allow mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close the valve(s) tightly and reset the boiler to clear the error code.
Your boiler has lost its connection to the electrical power supply and cannot function until power is restored.
Check your home's fuse box or consumer unit to see if a trip switch has been activated.Ensure the fused spur switch located near the boiler is turned on.Check that the plug, if present, is pushed firmly into the socket.
Your boiler has detected that the water returning from your radiators is dangerously hot, causing the system to shut down to prevent damage.
Full guide for 1 9on the Saunier Duval Ecosy
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Saunier Duval shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue