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

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

AA 7777 High

Boiler Fault Code AA 7777

Also written as AA7777 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code AA 7777 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning 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. (As reported on Ariston Clas One)

Pick your boiler brand for the AA 7777 fix

Ariston AA 7777 1 model

Source

Information for the AA 7777 fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026