Should underground approved duct be encased and sloped for drainage?

The correct answer is that underground approved duct should indeed be encased and sloped for drainage. This practice is important to prevent moisture accumulation, which can lead to a variety of issues, including mold growth, duct degradation, and reduced system efficiency.

Encasing the duct helps to provide additional protection against external elements, including water, soil, and potential physical damage from the surrounding environment. It ensures that the ductwork is insulated from contaminants that could affect the air quality and performance of the HVAC system.

Sloping the duct for drainage is crucial because it allows any condensation or water infiltration to flow away rather than pool within the ductwork. This kind of preventative measure is particularly essential in underground installations, where natural moisture from the ground can be more prevalent.

These considerations align with best practices in HVAC installation and maintenance, making sure that systems operate effectively and maintain their longevity.