G2 Gas Fitter Practice Exam

An indication of excessive primary air is typically represented by a:

1. Lifting flame

2. Stable flame

3. Pale blue flame

4. Flickering flame

The correct answer is: Lifting flame

An indication of excessive primary air is typically represented by a lifting flame. When there is too much primary air entering the combustion process, it can cause the flame to lift away from the burner surface. This is because the increased air supply can create a more volatile and unstable combustion environment, resulting in the flame not being anchored properly to the burner. A lifting flame can lead to incomplete combustion and increased levels of unburned gases, which can be a safety concern. Other flame characteristics, like a stable flame, suggest that combustion is occurring properly with the correct mixture of fuel and air. A pale blue flame generally indicates good combustion efficiency and the right amount of air, while a flickering flame often points to unstable combustion conditions but not necessarily excess primary air.