Low Information
63:1 on Viessmann Vitodens 300-W

Your boiler is performing a routine automatic safety check and system cleaning once a day to ensure everything is working correctly.

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

Additional function: 1x daily

What causes this fault?

This code appears when the boiler executes its automated self-maintenance routine designed to protect internal moving parts. It physically cycles the internal pump and valves for a brief moment to prevent them from becoming stuck due to inactivity. This is a normal operational feature and does not indicate that anything has broken or failed.

This is more noticeable during summer months when the heating is rarely used, as the boiler must manually trigger the pump to prevent it from seizing.

DIY fix possible

No action required; this is a normal operating status message rather than a breakdown.Monitor the display to ensure it returns to the standard temperature reading automatically.If the code stays on the screen permanently, try a simple reset.

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