What is a common indicator of inadequate primary air supply?

The orange-yellow coloration of flames is a significant indicator of inadequate primary air supply. When there is insufficient primary air mixing with the gas before combustion, it leads to incomplete combustion. The flame tends to exhibit an orange or yellow hue due to the presence of unburned carbon particles and other byproducts. This coloration is a clear sign that the burner is not performing efficiently, and it can be an indication of a safety concern, as incomplete combustion can lead to the production of carbon monoxide.

In contrast, steady and bright flames typically suggest a healthy air-to-gas ratio, indicating that the burner is fulfilling its combustion needs effectively. Consistent gas consumption would imply that the appliance is running normally without showing signs of inefficiency, while minimal sound from the burner might suggest normal operation as well but doesn’t specifically indicate any issues with air supply. Therefore, the orange-yellow flame coloration is the most straightforward and reliable signal indicating a problem with the primary air supply.