Your boiler has lost power while it was already trying to report a different error, meaning the system is currently confused and needs a manual reset to restart correctly.

DIY fix possible

Locate the reset button or dial on the front of your boiler control panel.Hold the reset button for 3 to 5 seconds until the display clears.Wait a few minutes to see if the boiler initiates a new start-up sequence.If the code returns, try switching the boiler off at the fused spur for 60 seconds before turning it back on.