How much does it cost to fix Ariston error code AA 7777?

Typical repair cost for the Ariston AA 7777 fault is £120-220 including labour.

AA 7777 High

Ariston AA 7777 Fault Code

Q: What does the Ariston AA 7777 fault code mean?

Your boiler has detected that the internal system used to drain away water produced during heating is not working correctly, causing the system to stop for safety.

Also written as AA7777 — same fault.

The Ariston AA 7777 fault code means: your boiler has detected that the internal system used to drain away water produced during heating is not working correctly, causing the system to stop for safety.. It appears on 1 Ariston model in our database.

Technical description: Condensate Trap full of water Condensate sensor short circuited Condensate sensor in open circuit

Typical repair cost £120-220 (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 AA 7777 fault code

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

Clas One Repair: £120-220

Source

Ariston AA 7777 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