Low Information
81:0 on Viessmann Vitodens 333-F

Your boiler has been manually switched to a mode where it only provides hot water and has turned the central heating off for the season.

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

Manual summer/winter changeover

What causes this fault?

This code appears when the boiler's control settings have been intentionally adjusted to turn off the central heating while keeping the hot water active. It is triggered by a manual user selection on the control panel, often done to save energy when heating isn't needed. There is no mechanical failure; the boiler is simply following a command to operate in 'hot water only' mode.

This code is most frequently seen during the spring and summer months when homeowners manually switch over to summer mode.

DIY fix possible

Locate the control panel on the front of the boilerAccess the menu settings to find 'Heating and Hot Water' modeSwitch the setting from 'Summer mode' back to 'Heating and Hot Water' to re-enable your radiators

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