NATE Gas Heating Exam question and answers 2023

NATE Gas Heating Exam question and answers 2023Since 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% C: 78% Many pre-1992 furnaces have efficiencies around _______. A: 10% B: 40% C: 60% D: 80% C: 60% Today, furnaces with AFUE ratings greater than _____ are available. A: 85% B: 90% C: 100% D: 110% 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 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 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 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" C: 3.5" Burning one cubic foot of natural gas releases approximately _____ btu. A: 800 B: 1,050 C: 12,000 D: 15,000 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 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 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 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 A: Fuel, oxygen and ignition Which of the following is a natural result of combustion? A: Water vapor B: Carbon monoxide C: Carbon dioxide D: All of the above A: Water vapor 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 A: Is mixed with the fuel before the fuel reaches the burner 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 B: Is mixed with the fuel at the burner after the fuel has ignited The three major furnace configurations are: A: Up-flow, down-flow and lowboy B: Up-flow, down-flow and horizontal C: Up-flow, down-flow and cross-flow D: None of these is correct B: Up-flow, down-flow and horizontal Residential gas furnaces use blowers powered by which types of motors? A: Poly-phase, two phase, single phase and capacitor start B: Shaded pole, split-phase, capacitor start and PSC C: Three phase, shaded pole and PSC D: Split-phase, induction start-induction run and variable speed DC D: Split-phase, induction start-induction run and variable speed DC The horsepower range of residential heating blower motors is: A: 1⁄8 to 1⁄16 hp B: 1⁄4 to 1⁄2 hp C: 1⁄2 to 2 hp D: 3⁄4 to 2 hp B: 1⁄4 to 1⁄2 hp A heat anticipator is wired: A: In series with the "W" terminal B: In parallel with the "W" terminal C: In series with the "R" terminal D: In parallel with the "R" terminal A: In series with the "W" terminal Placing a jumper wire between the "R" terminal and the "G" terminal on a thermostat subbase will energize the: A: Gas valve B: Indoor fan motor C: Outdoor fan motor D: Compressor B: Indoor fan motor Placing a jumper wire between the "R" terminal and the "W" terminal on a thermostat sub-base will energize the: A: Gas valve B: Indoor fan motor C: Outdoor fan motor D: Compressor A: Gas valve Carbon monoxide is a: A: Product of incomplete combustion B: Poisonous gas C: Odorless gas D: All of the above are correct D: All of the above are correct The chemical symbol for carbon monoxide is: A: CO2 B: CO C: H2O D: NH3 B: CO Selecting a lower speed tap setting on a furnace indoor blower motor will cause: A: The temperature rise through the furnace to increase B: The temperature rise through the furnace to decrease C: The temperature rise through the furnace will not be affected D: The furnace to act as a humidifier A: The temperature rise through the furnace to increase "Carry over" channels or "cross overs" are used to: A: Carry unused excess fuel back to the flue where it is sent up the stack B: Carry primary air to the heat exchanger C: Carry secondary air to the heat exchanger D: Carry the flame from the first burner that lights to the remaining burners D: Carry the flame from the first burner that lights to the remaining burners Modern high-efficiency burners use combustion blowers. What are the two major types of combustion blowers? A: Induced draft and forced draft B: High pressure and low pressure C: Impeller type and centrifugal type D: Liquid and vapor types A: Induced draft and forced draft