What is the minimum clearance above grade for a furnace that has been factory sealed to prevent water entry?

The minimum clearance above grade for a furnace that has been factory sealed to prevent water entry is set at 2 inches. This standard is vital for ensuring that the furnace operates safely and effectively. The 2-inch clearance allows for proper drainage of water and prevents any potential buildup around the unit, which could lead to moisture intrusion or corrosion over time, even if the unit is factory sealed.

This clearance also aligns with safety regulations and manufacturer recommendations, ensuring that the furnace is installed in a way that minimizes the risk of water damage, especially in areas prone to flooding or high moisture. Proper installation and adherence to these clearance requirements are essential for maintaining the furnace's efficiency, longevity, and safe operation.