BoilerFaultCodesYour boiler is currently running in a special engineer's test mode used to check emissions and is not experiencing a mechanical breakdown.
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: Chimney sweeper cycle
What causes this fault?
This status occurs when the internal 'chimney sweeper' selector has been manually turned or left in the test position by an engineer. It physically forces the boiler to run at its highest or lowest power setting so that gas combustion levels can be measured accurately. It is not a component failure, but rather a specific operating mode used during servicing.
This is often seen shortly after an annual service or safety check if the technician forgets to return the dial to the normal heating position.
DIY fix possible
Check the mode selector dial is not set to the 'test' or 'chimney' iconTurn the selector dial to the 'OFF/RESET' position for a few secondsTurn the dial back to the 'ON' or 'Winter' position to resume normal operation
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