How much does it cost to fix Ariston error code 8.?

Typical repair cost for the Ariston 8. fault is £90-180 including labour.

8. High

Ariston 8. Fault Code

Q: What does the Ariston 8. fault code mean?

Your boiler is failing to detect that you need heating or hot water, often because one of its internal sensors or control knobs is faulty.

Also written as 8 — same fault.

The Ariston 8. fault code means: your boiler is failing to detect that you need heating or hot water, often because one of its internal sensors or control knobs is faulty.. It appears on 1 Ariston model in our database.

Technical description: There is no demand of heat due to the internal regulations of the boiler (Chw or Dhw probe/potentiometer issues)

Typical repair cost £90-180 (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 8. fault code

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

DIA 80 Repair: £90-180

Source

Ariston 8. 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