How much does it cost to fix Ariston error code 7 05?

Typical repair cost for the Ariston 7 05 fault is £150-250 including labour.

7 05 High

Ariston 7 05 Fault Code

Q: What does the Ariston 7 05 fault code mean?

Your boiler is struggling to detect water flow between its internal heating circuits, which means it will likely stop providing heating and hot water until the faulty sensor is replaced.

Also written as 705 — same fault.

The Ariston 7 05 fault code means: your boiler is struggling to detect water flow between its internal heating circuits, which means it will likely stop providing heating and hot water until the faulty sensor is replaced.. It appears on 9 Ariston models in our database.

Technical description: Hydraulic separation sensor defective

Typical repair cost £150-250 (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 7 05 fault code

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

Source

Ariston 7 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