What major concern does a floor drain in the furnace utility room present when installing a sump depressurization system?

The concern regarding potential back-drafting of the furnace when installing a sump depressurization system is significant due to the nature of air movement within a building. When such a system is installed, it can create a negative pressure within the space, which may inadvertently affect how combustion appliances, like a furnace, draw air for proper operation. This negative pressure can lead to back-drafting, where exhaust gases intended to exit the building through the flue can be pulled back into the living space instead. This is dangerous, as it can expose occupants to carbon monoxide and other harmful gases.

Proper ventilation and air pressure management are critical in spaces with combustion appliances. If not correctly addressed, the installation of a sump depressurization system in such an environment raises safety hazards that must be carefully evaluated.

The other options have their own concerns—such as increased humidity potentially affecting comfort and air quality, sump overflow posing risks of flooding or structural damage, and drainage issues during wet seasons—but none directly relate to critical safety risks linked to combustion appliances like back-drafting can.