Your boiler is currently in a manual testing mode used by engineers rather than broken, which is why it has stopped heating your home or water as usual.

Not a fault code Service mode selected to min, press service button to return to normal.

What causes this fault?

This occurs when the service button has been pressed or held, accidentally putting the boiler into its manual 'Minimum' testing mode. It is not caused by a mechanical failure, but rather the internal software waiting for an engineer to finish checking the system. Because it is stuck at a low output, it might seem like the boiler is underperforming or ignoring your thermostat.