G2 Gas Fitter Practice Exam

The appropriate vent system for a recessed furnace set into a wall is the B-W vent. This type of vent is specifically designed to accommodate the requirements of appliances that are installed within the confines of a structure, such as a wall-mounted or recessed furnace.

B-W vent systems are constructed to ensure efficient exhaust of flue gases while providing the necessary safety features. They are typically installed vertically and offer better draft characteristics suitable for the design of recessed furnaces. Proper venting helps to mitigate risks such as gas build-up and ensures compliance with building codes regarding gas appliance installations.

Centrifugal vents, while effective in other applications, are not typically suited for recessed installations due to their design, which is geared towards creating airflow through forced means rather than natural venting. Single wall vents do not provide the necessary safety and efficiency for a recessed furnace. Ventless systems eliminate the need for venting but are not appropriate for this scenario, as they can pose significant safety risks and are often restricted by regulations for gas appliances.