Gas Heat ESCO Practice Exam

What percentage of carbon monoxide (CO) is acceptable in a sample of the flue gas in a gas furnace?

1. 0.02%

2. 0.04%

3. 0.06%

4. 0.08%

The correct answer is: 0.04%

Excessive levels of carbon monoxide (CO) in the flue gas of a gas furnace can pose a serious health hazard. Therefore, it is important to regularly check and monitor the CO levels. The acceptable range for CO in the flue gas is typically 0.02% to 0.04%. Choice A is too low, while choices C and D are too high and indicate a potential issue with the furnace. It is important to address any levels above 0.04% to ensure proper functioning of the furnace and safety for occupants.