NATE GAS HEATING COMPREHENSIVE
REVIEW 2026 VERIFIED QUESTIONS AND
SOLUTIONS
◉furnace efficiency is calculated by. Answer: useful output divided
by input
◉combustion efficiency is. Answer: an index of the useful heat
obtained from the gas being burned
◉AFUE (Annual Fuel Utilization Efficiency) is. Answer: a percentage
of the annual average efficiency of a furnace as determined by
laboratory tests
◉all furnaces manufactured after what year must have an AFUE
rating?. Answer: 1985
◉all furnaces manufacturers after 1992 must have an AFUE of at
least. Answer: 78%
◉natural draft furnaces rely on the. Answer: buoyancy of the hot
combustion products to create the draft needed to draw exhaust
through the heat exchanger and out the vent
,◉it is difficult for natural draft furnaces to obtain a. Answer: 78%
AFUE rating
◉induced draft furnaces have an AFUE of at least. Answer: 78%
◉induced draft furnaces use. Answer: an induced draft fan to draw
the products of combustion through the heat exchanger
◉an induced draft fan restricts. Answer: the flow of warm air out the
vent during the off cycle
◉condensing furnaces have an AFUE rating of at least. Answer: 90%
◉condensing furnaces have an additional/ secondary. Answer: Heat
exchanger which removes the latent from the flue gas by condensing
the water vapor
◉the secondary heat exchanger is mounted directly over. Answer:
the discharge of the blower
◉condensed furnaces are designed for. Answer: side wall venting or
roof termination
,◉most condensing furnaces are designed to draw. Answer: 100% of
combustion air from outside
◉the induced draft motor pulls the hot flue games out of the.
Answer: first heat exchanger then through the secondary heat
exchanger
◉the four furnace configurations are. Answer: up flow, down flow,
horizontal left or right, and multi-pose
◉common types of fuels used on gas fired furnaces are. Answer:
natural (methane), manufactured and mixed gases, and LPG
(liquefied petroleum gas)
◉most furnaces are shipped to burn only one type of fuel but.
Answer: field conversion kits may be available to convert to another
type of fuel
◉natural gas consists of approximately:. Answer: 90% methane
(CH4), 5% Ethan (C2H6), and 5% propane (C3H8)
◉natural gas is formed from. Answer: the remains of plants and
animal life which existed on the earth millions of years ago
, ◉liquefied petroleum games are mainly. Answer: propane or butane,
sometimes a mixture of the two
◉liquefied petroleum games are obtained from. Answer: natural gas
orasabyproduct from refining oil
◉liquefied petroleum games are usually transported and stored in.
Answer: a liquid form
◉propane has a boiling point of. Answer: -44 degrees Fahrenheit
◉one cubic foot of propane requires. Answer: 24 cubic feet of air to
support proper combustion
◉ignition temperature is the minimum temperature at which.
Answer: the combustion reaction starts
◉natural gas has an ignition temperature of approximately. Answer:
1170 degrees Fahrenheit
◉propane has an ignition temperature of approximately. Answer:
932 degrees Fahrenheit
REVIEW 2026 VERIFIED QUESTIONS AND
SOLUTIONS
◉furnace efficiency is calculated by. Answer: useful output divided
by input
◉combustion efficiency is. Answer: an index of the useful heat
obtained from the gas being burned
◉AFUE (Annual Fuel Utilization Efficiency) is. Answer: a percentage
of the annual average efficiency of a furnace as determined by
laboratory tests
◉all furnaces manufactured after what year must have an AFUE
rating?. Answer: 1985
◉all furnaces manufacturers after 1992 must have an AFUE of at
least. Answer: 78%
◉natural draft furnaces rely on the. Answer: buoyancy of the hot
combustion products to create the draft needed to draw exhaust
through the heat exchanger and out the vent
,◉it is difficult for natural draft furnaces to obtain a. Answer: 78%
AFUE rating
◉induced draft furnaces have an AFUE of at least. Answer: 78%
◉induced draft furnaces use. Answer: an induced draft fan to draw
the products of combustion through the heat exchanger
◉an induced draft fan restricts. Answer: the flow of warm air out the
vent during the off cycle
◉condensing furnaces have an AFUE rating of at least. Answer: 90%
◉condensing furnaces have an additional/ secondary. Answer: Heat
exchanger which removes the latent from the flue gas by condensing
the water vapor
◉the secondary heat exchanger is mounted directly over. Answer:
the discharge of the blower
◉condensed furnaces are designed for. Answer: side wall venting or
roof termination
,◉most condensing furnaces are designed to draw. Answer: 100% of
combustion air from outside
◉the induced draft motor pulls the hot flue games out of the.
Answer: first heat exchanger then through the secondary heat
exchanger
◉the four furnace configurations are. Answer: up flow, down flow,
horizontal left or right, and multi-pose
◉common types of fuels used on gas fired furnaces are. Answer:
natural (methane), manufactured and mixed gases, and LPG
(liquefied petroleum gas)
◉most furnaces are shipped to burn only one type of fuel but.
Answer: field conversion kits may be available to convert to another
type of fuel
◉natural gas consists of approximately:. Answer: 90% methane
(CH4), 5% Ethan (C2H6), and 5% propane (C3H8)
◉natural gas is formed from. Answer: the remains of plants and
animal life which existed on the earth millions of years ago
, ◉liquefied petroleum games are mainly. Answer: propane or butane,
sometimes a mixture of the two
◉liquefied petroleum games are obtained from. Answer: natural gas
orasabyproduct from refining oil
◉liquefied petroleum games are usually transported and stored in.
Answer: a liquid form
◉propane has a boiling point of. Answer: -44 degrees Fahrenheit
◉one cubic foot of propane requires. Answer: 24 cubic feet of air to
support proper combustion
◉ignition temperature is the minimum temperature at which.
Answer: the combustion reaction starts
◉natural gas has an ignition temperature of approximately. Answer:
1170 degrees Fahrenheit
◉propane has an ignition temperature of approximately. Answer:
932 degrees Fahrenheit
