E61 665 High

Ariston E61 665 Fault Code

Also written as E61665 — same fault.

The Ariston E61 665 fault code means: your boiler has detected an issue with its internal hardware settings regarding how it processes fuel, which is preventing it from lighting safely.. It appears on 1 Ariston model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Burner jet 1.30 full kit (natural gas)
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 E61 665 fault code

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

Source

Ariston E61 665 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 7 July 2026