How much does it cost to fix Ariston error code S 30?

Typical repair cost for the Ariston S 30 fault is £60-140 including labour.

S 30 Low

Ariston S 30 Fault Code

Q: What does the Ariston S 30 fault code mean?

Your boiler has lost signal from the temperature sensor located outside your home, meaning it doesn't know how hard it needs to work to match the outdoor weather.

Also written as S30 — same fault.

The Ariston S 30 fault code means: your boiler has lost signal from the temperature sensor located outside your home, meaning it doesn't know how hard it needs to work to match the outdoor weather.. It appears on 5 Ariston models in our database.

Technical description: External sensor open circuit

Typical repair cost £60-140 (including labour)

DIY fix possible

Check the external sensor on your outside wall for any obvious damage or loose wiresInspect the cable running from the sensor to the house for breaks or animal chewsReset the boiler to see if the communication error clears

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Ariston models that show the S 30 fault code

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

Source

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

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026