What is the minimum distance that the vent from a 75,000 Btuh Category 3 furnace may terminate from a door?

The correct answer is based on the National Fuel Gas Code and the requirements for venting appliances, particularly Category 3 gas furnaces. For a 75,000 Btuh Category 3 furnace, the minimum distance for vent termination from a door is established as 3 feet.

This requirement is in place primarily for safety and to ensure proper venting of combustion gases. A distance of 3 feet helps to minimize the possibility of exhaust gases re-entering the building through doors or windows, which could pose a risk of exposure to harmful byproducts of combustion, such as carbon monoxide.

Other distances mentioned do not comply with the specific regulations set forth for the venting of this type of furnace. A lesser distance could lead to safety risks, while a greater distance, while safe, might not be necessary and could lead to unnecessary complications or challenges in installation.