Low
D.91 on Vaillant Combi Compact 282EB

Your boiler's external temperature sensor is communicating its status, but the system is having trouble processing the radio signal correctly.

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

DIY fix possible

Check that the batteries in your external outdoor sensor are still workingEnsure there are no large metal objects blocking the signal between the sensor and the boilerTry resetting the boiler to see if the status clears

Find a Gas Safe engineer
Search the official register →

Related fault codes

D.90View →

Related guides you might find useful

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →