Where should the combustion air inlet and flue gas outlet of a direct vent appliance terminate in relation to each other?

The correct response indicates that the combustion air inlet and flue gas outlet of a direct vent appliance should terminate in the same plane and ambient pressure zone. This setup is crucial for ensuring safe and efficient operation of the appliance. When both the air inlet and flue gas outlet are positioned in the same plane, it helps to maintain consistent pressure and minimize the risk of flue gases being drawn back into the combustion air intake.

In this configuration, the ambient pressure remains stable, allowing the appliance to draw in fresh air for combustion without interference from wind or atmospheric fluctuations. This prevents issues such as backdrafting, where exhaust gases could potentially enter the living space, which could lead to hazardous conditions.

Other options suggest alternatives that could create imbalances in pressure or airflow, thereby compromising the efficiency and safety of the appliance's operation. Keeping both elements in the same plane and ambient pressure zone provides a reliable and effective means of managing combustion air and flue gases.