NATE Gas Heating Exam Questions Fully Solved 2026/27

Since 1992, the United States Department of Energy has required that all furnaces sold and installed from that date on must have an AFUE of no less than: A: 70% B: 75% C: 78% D: 80% - Correct Answer C: 78% Many pre-1992 furnaces have efficiencies around _______. A: 10% B: 40% C: 60% D: 80% - Correct Answer C: 60% Today, furnaces with AFUE ratings greater than _____ are available. A: 85% B: 90% C: 100% D: 110% - Correct Answer B: 90% A thermocouple is used with: A: Intermittent pilot systems B: Direct spark ignition systems C: Glow coil ignition systems D: Standing pilot ignition systems - Correct Answer D: Standing pilot ignition systems The purpose of the gas pressure regulator is to: A: Keep the color of the flame constant B: Keep the high limit switch from tripping C: Maintain a constant gas pressure at the burner D: Allow the gas valve to operate smoothly and accurately - Correct Answer C: Maintain a constant gas pressure at the burner The instrument used to measure outlet gas pressure is the: A: Velometer B: Anemometer C: Monometer D: Draft gauge - Correct Answer C: Monometer The regulator on a natural gas furnace should be adjusted to supply _____ inches of pressure at the burners. A: 11" B: 10" C: 3.5" D: 2" - Correct Answer C: 3.5" Burning one cubic foot of natural gas releases approximately _____ btu. A: 800 B: 1,050 C: 12,000 D: 15,000 - Correct Answer B: 1,050 Under ideal conditions natural gas has an ignition temperature of _______ degrees F and a burning temperature of ________ degrees F. A: 800 degrees, 1000 degrees B: 1,100 degrees, 3,500 degrees C: 1,100 degrees, 5,000 degrees D: 2,500 degrees, 8,000 degrees - Correct Answer B: 1,100 degrees, 3,500 degrees Propane and butane are both: A: Lighter than air B: Heavier than air C: Weigh the same as air D: None of the above - Correct Answer B: Heavier than air In order to achieve complete combustion with natural gas, each cubic foot of gas must combine with no less than ______ cubic feet of air with an additional 5 cubic feet of extra air to ensure there is enough oxygen for complete combustion. A: 5 cubic feet B: 10 cubic feet C: 15 cubic feet D: 20 cubic feet - Correct Answer B: 10 cubic feet The three elements of combustion are: A: Fuel, oxygen and ignition B: Nitrogen, oxygen and heat C: Air, fuel and oxygen D: Air, fuel and nitrogen - Correct Answer A: Fuel, oxygen and ignition Which of the following is a natural result of combustion? A: Water vapor B: Carbon monoxide