High
8 03 on Ariston Genus ONE+ WiFi

Your boiler's electronic brain is confused because it has detected a configuration error between its settings and its internal heating capacity.

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

Mismatch kW Size, ID combustion

From this model's manual
Verified against the Ariston Genus One Net installation & service manual, page 37.
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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Related fault codes

8 02View →8 04View →

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