NATE Gas Heating Exam Verified Questions and answers 2023 Latest Update

NATE Gas Heating Exam Verified Questions and answers 2023 Latest Update 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 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 Under ideal conditions natural gas has an ignition temperature of degrees F C: Carbon dioxide D:All of the above - correct answer 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 - correct answer 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 - correct answer 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 - correct answer 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 - correct answer 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 - correct answer 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 - correct answer 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 - correct answer 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 - correct answer 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 - correct answer D:All of the above are correct The chemical symbol for carbon monoxide is: A: CO2 B: CO C: H2O D: NH3 - correct answer 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 - correct answer 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 - correct answer 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 - correct answer A: Induced draft and forced draft The purpose of the combustion blower is to: A: Cause an adequate amount of oxygen-rich air to mix with the fuel for better combustion B: Push the products of combustion out of the building C: Prevent carbon monoxide from entering the heat exchanger D: Give the larger blower motor a rest - correct answer A: Cause an adequate amount of oxygen-rich air to mix with the fuel for better combustion Heat transfers from an object or area at a higher temperature to an object or area at a lower temperature. A heated heat exchanger transfers heat to the air by: A: Conduction B: Natural convection C: Radiation D: Forced convection - correct answer D: Forced convection The voltage that creates a spark on a spark ignition system is approximately: A: 240 volts B: 5,000 volts C: 15,000 volts D: 25,000 volts - correct answer C: 15,000 volts The capacity of a natural gas furnace is de-rated by for every 1000 feet above sea level: A: 1% B: 2% C: 3% D: 4% - correct answer D: 4% A crack in a heat exchanger can: A:Allow combustion gases to mix with the space air B: Prevent the heat from effectively transferring to the air C: Cause the high-limit control to shut the furnace down D: Cause the furnace to catch on fire - correct answer A: Allow combustion gases to mix with the space air Gas valves operate on what voltage? A: 12 volts B: 24 volts C: 120 volts D: 230 volts - correct answer B: 24 volts Mid-efficiency furnaces operate with flue gas temperatures between: A: 275 and 360 degrees B: 200 and 500 degrees C: 100 and 275 degrees D: 80 and 100 degrees - correct answer A: 275 and 360 degrees High-efficiency furnaces operate with flue gas temperatures between: A: 275 and 360 degrees B: 200 and 500 degrees C: 100 and 275 degrees D: 80 and 100 degrees - correct answer C: 100 and 275 degrees "B" vent is: