BoilerFaultCodesThe 6 most common faults
Your boiler has stopped heating the water because it cannot move the water around the system effectively.
Check your boiler pressure gauge; if it is below 1 bar, use the filling loop to top it up to 1.5 barTurn the boiler off at the mains for 60 seconds and then turn it back on to reset the systemCheck that your heating programmer or thermostat is set to 'on' to ensure the boiler is being asked to run
Your boiler has detected that water is not flowing properly around your heating system, so it has shut down to prevent damage.
Check your central heating pressure gauge to ensure it is between 1 and 1.5 barIf the pressure is low, use the filling loop to top it up to the correct levelEnsure all radiator valves are fully open to allow water to circulate
Your boiler has detected that there is not enough water circulating inside the system to operate safely.
Locate the external filling loop, which is a silver braided hose connecting two pipes near your boiler.Open the valves on both ends of the filling loop to allow water into the system.Watch the pressure gauge on the front of the boiler and close both valves firmly once the needle reaches 1.5 bar.
Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage.
Full guide for A 01Your boiler is trying to start but cannot detect a flame, so it has safely shut itself down to prevent gas from building up.
Full guide for A 03Your boiler's internal computer has encountered a critical error, which is preventing it from safely starting or controlling your heating system.
Full guide for A 37on the Chaffoteaux Minima HE System 24
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 Chaffoteaux 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