How much of the bottom compartment should be factory sealed in a furnace to prevent water entry?

In a furnace, particularly in contexts where water entry could pose significant operational issues or safety hazards, it is crucial to maintain proper sealing of the bottom compartment. The correct distance to ensure that water does not seep into these compartments is 2 inches. This specification balances effective moisture prevention while allowing necessary airflow for the furnace's combustion processes and overall functionality.

Sealing the bottom compartment to a depth of 2 inches creates a barrier that heightens the furnace’s resilience against water ingress, especially in areas prone to flooding or where water accumulation is common. Ensuring this level of sealing helps maintain the integrity of the furnace, contributing to its efficient operation and longevity. The other depths provided are overly prohibitive and may not be necessary or practical within typical installation parameters, hence understanding the specific requirements helps in correctly applying industry standards.