What can happen if a gas furnace fuel-air mixture is too rich?

When the fuel-air mixture in a gas furnace is too rich, it means that there is an excess of fuel in relation to the amount of air available for combustion. This imbalance results in a situation where not all of the fuel can burn completely. As a consequence, incomplete combustion occurs, leading to several potential issues, such as the production of carbon monoxide, soot accumulation, and a decrease in the overall efficiency of the furnace. Incomplete combustion is a critical concern because it can result in unsafe conditions within the heating system and reduced heating output. Recognizing the signs of a rich mixture is essential for maintaining safety and efficiency in gas furnace operation.