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
... [Show More] 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 -
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