Emergency
5 03 on Ariston Genus ONE+ WiFi

Your boiler has detected a flame when it should be turned off, which is a significant safety precaution indicating it cannot shut down its fuel supply properly.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Flame detected with gas valve closed (After 20 seconds with 502)

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

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