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Anti-frost device on Ariston Excalibur

Your boiler has detected that the water inside is getting too cold and has automatically turned on its internal heater to prevent the pipes from freezing.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Pump activates if water temperature falls below 8°C until 18°C is attained; further protection triggers if temperature falls below 3°C.

From this model's manual
Verified against the Ariston Excalibur 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.

DIY fix possible

Ensure the boiler remains plugged in and the power supply is switched onCheck that your gas supply is active so the burner can fire if neededOpen any radiator valves in colder rooms to allow water to circulate freely

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