Gas Heat ESCO Practice Exam

Which furnace type is associated with a flue gas temperature range of 280 F - 300 F?

1. Category I

2. Category II

3. Category III

4. Category IV

The correct answer is: Category I

A furnace type associated with a flue gas temperature range of 280 F - 300 F is Category I. This type of furnace is typically used for natural draft or atmospheric venting systems and uses conventional vertical venting. Category II, III, and IV furnaces are not associated with this temperature range. Category II furnaces have a higher flue gas temperature range, between 300 F - 450 F, and use a mechanical draft system. Category III and IV furnaces utilize a condensing technology and have a lower flue gas temperature range of less than 200 F. These types of furnaces are not associated with the given temperature range.