What is the role of a pilot light in a gas appliance?

The role of a pilot light in a gas appliance is to ignite the main burner gas. It serves as a continuous flame that provides the necessary heat to start the combustion process when gas is released from the main burner. When the appliance is turned on, the gas flows to the burner, and the pilot light ignites this gas, allowing the appliance to operate efficiently and safely.

The pilot light remains lit at all times, creating a reliable ignition source that ensures the main burner can ignite quickly when it is needed. This is particularly important in appliances such as furnaces, water heaters, and stoves. Without the pilot light, the main burner would have no source of ignition, leading to inefficiencies or unsafe conditions.

The other options, while relevant to gas systems, do not accurately describe the primary function of a pilot light. For instance, while temperature monitoring plays a crucial role in the operation of gas appliances, it is not a function of the pilot light itself. The same goes for system pressure maintenance and gas presence indication, which involve other components in the gas appliance system.