BoilerFaultCodesAtmos 23 Fault Code
The Atmos 23 fault code means: your boiler has detected a problem with one of its internal temperature sensors, meaning it cannot accurately monitor the water temperature and has stopped working as a safety precaution.. It appears on 4 Atmos models in our database.
Technical description: Sensor fault S2 — check wires for breaks; replace S2
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Atmos models that show the 23 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Atmos 23 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