How much does it cost to fix Ariston error code S 05?

Typical repair cost for the Ariston S 05 fault is £90-170 including labour.

S 05 Medium

Ariston S 05 Fault Code

Q: What does the Ariston S 05 fault code mean?

Your boiler has lost the ability to monitor the temperature of your hot water because a sensor has malfunctioned, which will likely prevent you from getting warm water at your taps.

Also written as S05 — same fault.

The Ariston S 05 fault code means: your boiler has lost the ability to monitor the temperature of your hot water because a sensor has malfunctioned, which will likely prevent you from getting warm water at your taps.. It appears on 5 Ariston models in our database.

Technical description: Short circuit on Domestic hot water sensor

Typical repair cost £90-170 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Ariston models that show the S 05 fault code

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

Source

Ariston S 05 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