High
AA9999 on Ariston Ecosystem 27 RFFI

Your boiler's computer is experiencing an internal error and cannot properly check or control the system, meaning it needs an expert to reset or replace the main control unit.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Problem with the electronic monitoring

From this model's manual
Verified against the Ariston Micro Condens System installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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