NATE_Gas_Heating_Exam_Questions_and_answers_2023 complete

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% - Many pre-1992 furnaces have efficiencies around . A: 10% B: 40% C: 60% D: 80% - Today, furnaces with AFUE ratings greater than are available. A: 85% B: 90% C: 100% D: 110% - A thermocouple is used with: A: Intermittent pilot systems B: Direct spark ignition systems C: Glow coil ignition systems 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 - The instrument used to measure outlet gas pressure is the: A: Velometer B: Anemometer C: Monometer D: Draft gauge - 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" - Burning one cubic foot of natural gas releases approximately btu. A: 800 B: 1,050 C: 12,000 D: 15,000 - 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 - Propane and butane are both: A: Lighter than air B: Heavier than air C: Weigh the same as air D: None of the above - 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 - 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 - Which of the following is a natural result of combustion? A: Water vapor B: Carbon monoxide C: Carbon dioxide D: All of the above - Primary air is air that: A: Is mixed with the fuel before the fuel reaches the burner B: Is mixed with the fuel at the burner after the fuel has ignited C: Remains unused after the combustion process is complete D: Enters the draft diverter and goes up the stack with the products of combustion - Secondary air is air that: A: Is mixed with the fuel before the fuel reaches the burner B: Is mixed with the fuel at the burner after the fuel has ignited C: Remains unused after the combustion process is complete D: Enters the draft diverter and goes up the stack with the products of combustion - ..................................................continued.....................................................