30 Medium

Atmos 30 Fault Code

The Atmos 30 fault code means: your boiler is struggling to detect the temperature of your hot water supply, which means it will likely stop providing hot water until the faulty sensor is fixed.. It appears on 4 Atmos models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Sensor fault hot water sensor S3
Typical repair cost £120-220 (including labour)

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 30 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Atmos 30 fault code information on this page is sourced and cross-checked against the official Atmos service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026