BoilerFaultCodesYour boiler is currently running in a special testing mode used by engineers to check emissions, and it should return to normal operation automatically after a short period.
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 sweep function is active
What causes this fault?
This code appears because the boiler has been manually put into a dedicated 'service mode' used for testing gas combustion levels. It is triggered when an engineer presses and holds the reset button for several seconds to force the boiler to run at its highest or lowest power. It is not a mechanical failure, but rather a status indicator that the system is currently being tested.
This code is more common during the autumn and winter months when homeowners typically book their annual boiler service or safety check.
DIY fix possible
Wait approximately 15 minutes for the test mode to time out automatically.Turn the selector switch or dial to the 'Off/Reset' position for a few seconds.Turn the selector back to the 'On' or 'Winter' position to resume normal heating.
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