Low Information
D.91 on Vaillant ecoTEC plus Regular

Your boiler is providing a status update about its connection to an outdoor temperature sensor used for the radio clock signal.

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

DCF status with connected external probe

What causes this fault?

This status code appears when the boiler is searching for or receiving a time signal via a weather compensation sensor installed outside. It happens when the system uses a radio clock to automatically set the date and time for your heating schedule. It is simply an indication that the external probe is communicating this data and does not mean your heating has broken down.

DIY fix possible

No action is required as this is a status code, not a breakdown fault.Check that the display shows the correct time and date.Ensure nothing is obstructing the external sensor on the outside wall.

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