Your boiler is in normal standby mode and is working correctly, ready to provide heating or hot water when you need it.

At stand-by with no faults

What causes this fault?

This is not actually a fault, but the boiler's way of showing it has power and is ready to work. It occurrs when there is no active demand for heating or hot water, meaning the internal components are simply waiting for a signal from your thermostat or tap. The light flashes once every six seconds to confirm the system is healthy and monitoring for its next task.