How much does it cost to fix boiler error code A99?

Typical repair cost for the boiler A99 fault is £250-£550 including labour.

A99 High

Boiler Fault Code A99

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code A99 appears across 1 boiler brand and 7 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's internal computer has encountered a communication error or software glitch that is preventing it from monitoring the system's safety and operation. (As reported on Ariston Genus Premium)

Pick your boiler brand for the A99 fix

Ariston A99 7 models

Source

Information for the A99 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