Your boiler is accidentally trying to use a feature it doesn't have, which is usually caused by a minor electronic glitch or a recent settings change.

This feature is not required on this appliance.

What causes this fault?

This fault occurs when the boiler's internal computer becomes confused and tries to activate a 'flue luxury' feature that wasn't designed for this specific model. It is usually triggered by a brief electrical surge or if the boiler's software settings have accidentally been changed during a service or repair. Most of the time, the boiler simply needs to be told which model it is again to clear the error.