What does a gas valve with 100% shut off indicate?

A gas valve with 100% shut off indicates that the gas flow is completely cut off to a specific component within the gas supply system. In the context of gas appliances, this typically refers to the pilot burner. The pilot burner is a small flame that ignites the main gas burner when needed.

When a gas valve states it provides 100% shut off, it ensures no gas can escape through that valve, thus preventing any potential leakage or hazard. In this case, if the gas supply to the pilot burner is completely shut off, it means that the pilot flame will extinguish, which is a critical safety feature. This cutoff ability is important for both operational purposes and safety, allowing maintenance or inspections to occur without the risk of gas escaping.