The lack of dilution air at the furnace may cause which condition?

Lack of dilution air at the furnace can lead to backdraft conditions. In a combustion system, dilution air is important because it helps ensure that combustion byproducts are adequately mixed and vented outside the home. When there isn’t enough dilution air, the combustion gases can be pushed back into the living space instead of being properly expelled, causing a backdraft.

This condition can arise in tightly sealed homes where air intake systems may not be able to provide enough fresh air for safe combustion. Backdraft can be dangerous as it may introduce toxic gases such as carbon monoxide into the home environment. Proper ventilation practices are essential to mitigate this risk, emphasizing the need for sufficient dilution air in any fuel-burning appliance's operation.