What is a common symptom of insufficient combustion air in gas appliances?

In gas appliances, insufficient combustion air leads to incomplete combustion of the fuel, which can result in the production of carbon monoxide (CO), a dangerous and potentially lethal gas. When there is inadequate air for combustion, not all of the gas is burned completely, leading to higher levels of CO in the exhaust. This is a critical safety concern as carbon monoxide is colorless and odorless, making it particularly hazardous, as it can accumulate in living spaces without any warning signs.

This understanding underscores the importance of ensuring that gas appliances have adequate ventilation and combustion air supply to operate safely and efficiently. Monitoring CO levels and ensuring proper airflow is essential for both appliance performance and occupant safety.

The other options may describe various conditions related to HVAC systems but do not specifically correlate with the consequences of insufficient combustion air in the context of gas appliances. Proper combustion air is crucial for optimizing combustion efficiency and preventing hazardous situations.