BoilerFaultCodesYour boiler is performing a routine self-cleaning process to remove air bubbles from the system and is not actually reporting a hardware fault.
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.
Technical description: Venting function (runs for 5 minutes, diverter valve moves between CH and DHW every 30s, pump alternates 50s on/10s off)
What causes this fault?
This occurs when the boiler is first powered on or has been reset after a period of inactivity. The system physically moves water and internal components to push trapped air out of the heat exchanger and pipework to prevent internal damage. It is a protective measure rather than a failure, usually triggered by a power cut or a system refill.
This is often seen in autumn when homeowners turn their heating back on for the first time or after engineers have performed an annual summer service.
DIY fix possible
Wait 5 minutes for the automatic venting cycle to completeEnsure your radiator valves are open to help air move through the systemCheck if the boiler display changes to '0' or a temperature once the 5 minutes have passed
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