How much does it cost to fix Ariston error code 6 04?

Typical repair cost for the Ariston 6 04 fault is £150-300 including labour.

6 04 Emergency

Ariston 6 04 Fault Code

Q: What does the Ariston 6 04 fault code mean?

Your boiler has detected that the internal fan responsible for safely removing exhaust gases is not spinning fast enough, causing the system to stop for safety reasons.

Also written as 604 — same fault.

The Ariston 6 04 fault code means: your boiler has detected that the internal fan responsible for safely removing exhaust gases is not spinning fast enough, causing the system to stop for safety reasons.. It appears on 9 Ariston models in our database.

Technical description: Insuffi cient fan speed

Typical repair cost £150-300 (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 6 04 fault code

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

Source

Ariston 6 04 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