BoilerFaultCodesThe 6 most common faults
Your boiler has shut down because it detected it was getting too hot or a temperature sensor has failed.
Check that your radiator valves are open to allow water to flow.Ensure your system pressure is topped up to between 1.0 and 1.5 bar.Wait 15 minutes for the unit to cool down, then press the 'Reset' button.
Your boiler has reached an unsafe temperature and shut down to prevent damage or overheating.
Check that all radiator valves are open to ensure water can flow properly.Ensure the central heating pump is not making unusual grinding noises.Try resetting the boiler using the reset button once the system has cooled down.
Your boiler is failing to light the gas to create a flame, meaning you will not have any heating or hot water until it is reset or repaired.
Check that your gas supply is turned on and that other gas appliances (like a hob) are working.Ensure your condensate pipe (the plastic pipe leading outside) isn't frozen if it is very cold weather.Press the 'Reset' button on the boiler control panel once to see if it restarts.
Your boiler has detected that water is heating up too quickly or moving in the wrong direction, which usually means the water isn't circulating properly through your radiators.
Check that your boiler pressure is between 1.0 and 1.5 barEnsure all radiator valves and isolation valves are fully openBleed your radiators to remove any trapped air pocketsReset the boiler once circulation is confirmed
Your boiler has stopped heating because it is unable to accurately measure the temperature of the water leaving the unit.
Full guide for 20Your boiler has detected an issue with the sensor that monitors water returning from your radiators, causing the system to stop running for safety.
Full guide for 40on the Atag iR Regular
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 Atag 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