Your boiler is currently receiving a request to heat your hot water, so it is working exactly as it should.

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What causes this fault?

This status occurs when the boiler receives a signal to heat your water but cannot start the burner because it has recently finished a heating cycle and needs to cool down internally. It is often caused by a communication lag between your external timer and the boiler, or a mechanical delay in the internal valve that directs water to your taps. In many cases, it is simply a 'waiting' state rather than a permanent mechanical failure.