BoilerFaultCodesAtmos 5 Fault Code
The Atmos 5 fault code means: 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.. It appears on 4 Atmos models in our database.
Technical description: No flame signal after 4 restart attempts — condensate discharge blocked; check gas valve setting. See TDS013 on atmos-i.co.uk.
DIY fix possible
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.
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Atmos models that show the 5 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Atmos 5 fault code information on this page is sourced and cross-checked against the official Atmos service / installation manuals for each affected model.
- Atmos Intercombi HE32 manual (PDF)
- Atmos Interopen HE22 manual (PDF)
- Atmos Intersystem HE26 manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026