Low Information
9C:5 to 9C:60 on Viessmann Vitodens 333-F

Your boiler is currently undergoing a pre-set maintenance test or a specialized calibration check that lasts between 5 and 60 minutes.

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.

Technical description

Time adjustable from 5 to 60 minutes

What causes this fault?

This code appears when the boiler has been manually put into a specialized service mode, such as a chimney sweep test or a manual calibration check. It is triggered by a user or engineer adjusting the settings to run the burner at a specific output for a set duration. Once the programmed time for this test elapses, the boiler will automatically return to its normal heating operation.

DIY fix possible

Wait for the timer to count down and the code to disappear naturallyCheck that you haven't accidentally entered a test mode via the control panelIf the code persists for over an hour, try a simple reset of the boiler

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