Which type of pilot light is commonly used in gas-fired appliances?

The standing pilot light is commonly used in gas-fired appliances because it provides a continuous flame that serves as an ignition source for the main burner whenever the appliance operates. This type of pilot is always lit, ensuring that gas can ignite immediately when the appliance is called to heat, making it reliable for continuous operation.

Standing pilots are particularly beneficial in applications where the appliance runs frequently, as they minimize the delay in heating. They are also advantageous in terms of simplicity and reliability, since they do not rely on electronic systems or complicated ignition processes.

In contrast, other types of pilot lights, such as the intermittent pilot and electronic spark, only ignite gas as needed. While these alternatives can be more fuel-efficient since they do not constantly burn gas when the appliance is off, they also come with more complex ignition systems and may introduce delays in heating. The flame sensor pilot is a more advanced technology often used in more modern appliances or in specific applications, which might not be as common in traditional gas-fired systems compared to the straightforward and effective standing pilot.