What can result from an incorrect air-to-gas ratio in a gas burner?

An incorrect air-to-gas ratio in a gas burner can lead to improper combustion, which can create safety hazards. When the air-to-gas ratio is not balanced correctly, it can result in incomplete combustion, producing carbon monoxide and unburned hydrocarbons. This not only reduces the efficiency of the burner but can also increase the risk of fire or explosion, making it a significant safety concern. Additionally, improper combustion can cause a malfunction in the burner, leading to further operational issues and potential hazards for users.

In contrast, the other options are associated with outcomes that are not aligned with what occurs when the air-to-gas ratio is incorrect. Increasing fuel efficiency and achieving lower emissions are results of optimal combustion that occurs with the correct ratios. A consistent flame color also indicates proper combustion; variations in flame appearance are often signs of an unbalanced mixture leading to safety risks.