BoilerFaultCodesThe 6 most common faults
01
4 High DIY-safe
Your boiler has tried to light itself four times but failed to create a flame, causing the system to shut down for safety.
What to try first
Check that your gas emergency control valve (gas tap) is fully open.If you have a pre-payment meter, ensure you have sufficient credit.Check if other gas appliances, like a hob, are working to confirm gas supply.Look for any frozen or blocked external condensate pipes and thaw them with warm water.
02
5 High DIY-safe
Your boiler has failed to light after several tries, often because the drainage pipe for waste water is blocked or there is a problem with the gas supply.
What to try first
Check if the external condensate pipe is frozen or blocked by debris.If frozen, thaw the pipe by pouring warm (not boiling) water over it.Ensure your gas meter has credit and other gas appliances are working.Press the reset button once to see if the boiler restarts.
03
6 High Engineer
Your boiler is failing to sense a flame, meaning it cannot stay on safely to provide heating or hot water.
Full guide for 604
8 High Engineer
Your boiler has been forced to stop working because the internal fan is not spinning at the correct speed to safely clear waste gases.
Full guide for 805
10 High Engineer
Your boiler's internal temperature sensor has stopped sending the correct signal, which means the system cannot heat your water or radiators safely.
Full guide for 1006
11 High Engineer
Your boiler has detected a problem with one of its internal temperature sensors, which means it cannot safely measure the heat of the water and has stopped working as a precaution.
Full guide for 11on the Atmos Intercombi HE32
Ignition electrodeGas valveIgnition transformerFlame sensing probeCondensate trapIgnition cable
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 Atmos 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