Your boiler has detected a lockout fault and has shut down to protect itself, meaning your heating and hot water will not work until it is reset.

Led alarm (red)

What causes this fault?

This fault occurs when the boiler fails to detect a flame after several ignition attempts, causing the system to shut down for safety. The most common reasons are a lack of gas supply to the unit, a blocked burner, or a faulty sensor that cannot confirm the flame is lit. It can also be caused by worn-out electrical components that are responsible for creating the initial spark.