The boiler's burner check was briefly interrupted because the conditions needed to set it up were not quite steady, which is usually a temporary hiccup rather than a sign of serious damage.

DIY fix possible

Press the reset button on the boiler (or use the reset option on the control panel) and wait about 10 minutes for it to restart and run its check again.Look at the pressure gauge on the front of the boiler. It should read between 1.0 and 1.5 bar when cold. If it is low, top it up using the filling loop, following the manufacturer's guide, then close the loop.Make sure no other gas appliances, such as a cooker or a second boiler, are running at full power while the boiler is starting, and check that the boiler's air vents and flue outlet outside are not blocked by leaves, snow or debris.If the code returns or the boiler stays off after these steps, stop trying to fix it and book a Gas Safe registered engineer.