BoilerFaultCodesThe 3 most common faults
Your boiler has switched itself off because it has detected that it is getting dangerously hot inside.
Turn the boiler off and allow it to cool down for 30 minutesEnsure all radiator valves are fully open to allow water to flowCheck that the system pressure is between 1 and 1.5 barReset the boiler using the control knob or button
Your boiler doesn't have enough water inside it to operate safely, which is why it has stopped working.
Locate the filling loop (usually a silver flexible hose) under the boiler.Slowly open the one or two taps/valves until you hear water entering the system.Watch the pressure gauge until it reaches between 1.0 and 1.5 bar, then close the valves tightly.
Your boiler has reached its maximum safe temperature and has shut down as a safety precaution to prevent overheating.
Check if any radiator valves are turned off and open them fully to allow water flow.Ensure your system pressure is between 1 and 1.5 bar on the pressure gauge.Try resetting the boiler via the control panel.
on the Baxi Luna 3 Comfort
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 Baxi 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