14399627
Descrição
Quiz por David Brown, atualizado more than 1 year ago
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Criado por David Brown
quase 6 anos atrás
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Questão 1
Questão
in a modern gas furnace, the component that separates the combustion gases from the supply air is the __________.
Responda
-
gas valve
-
heat exchanger
-
inducer fan
-
plenum box
Questão 2
Questão
what type of furnace moves warm air through the conditioned space without a fan?
Responda
-
gravity
-
horizontal
-
lowboy
-
upflow
Questão 3
Questão
furnace heat exchangers generally are made of ___________.
Responda
-
ceramic
-
copper
-
plastic
-
steel
Questão 4
Questão
what does AFUE stand for?
Responda
-
actual fuel usage efficiency
-
annual fuel utilization efficiency
-
annual furnace usage equivalency
-
approved fuel usage estimate
Questão 5
Questão
the main purpose of a secondary heat exchanger is to _________.
Responda
-
evaporate the flue gases
-
provide a backup containment
-
remove additional heat from the flue gases
-
reverse the primary air flow
Questão 6
Questão
which gas commonly used as a fuel in gas furnaces is heavier than air?
Responda
-
butane
-
isobutene
-
methane
-
propane
Questão 7
Questão
which grade of fuel oil is commonly used in residential furnaces
Responda
-
1
-
2
-
3
-
4
Questão 8
Questão
how many cubic feet of air are needed to burn 1 ft3 of natural gas
Responda
-
6
-
10
-
18
-
24
Questão 9
Questão
how many cubic feet of air are needed to burn 1 ft3 of propane
Responda
-
6
-
10
-
18
-
24
Questão 10
Questão
what is the approximate heat content of 1 ft3 of natural gas?
Responda
-
500 btu
-
800 btu
-
1050 btu
-
2500 btu
Questão 11
Questão
what is the approximate heat content of 1 ft3 of propane
Responda
-
500 btu
-
800 btu
-
1050 btu
-
2500 btu
Questão 12
Questão
what is the approximate heat content of one gallon of No.2 fuel oil?
Responda
-
75,000 to 90,000 btu
-
95,000 to 135,000 btu
-
137,000 to 142,000 btu
-
145,000 to 170,000 btu
Questão 13
Questão
what is a typical manifold pressure for a natural gas furnace?
Responda
-
3.5 in w.c.
-
11 in w.c.
-
2 psi
-
5 psi
Questão 14
Questão
what is the typical atmospheric manifold pressure for a propane furnace?
Responda
-
3.5 in w.c.
-
11 in w.c.
-
2 psi
-
5 psi
Questão 15
Questão
what type of furnace is commonly installed in a closet with underfloor supply ducts?
Responda
-
downflow
-
horizontal
-
lowboy
-
upflow
Questão 16
Questão
which of the following is required for combustion?
Responda
-
fuel
-
heat
-
oxygen
-
all of the above
Questão 17
Questão
which of the following is not a product of complete combustion?
Responda
-
carbon dioxide
-
carbon monoxide
-
heat
-
water
Questão 18
Questão
an unconfined space (in terms of furnace installation) is defined as a space with a volume equal to or greater than _______ per 1,000 btu of input rating
Responda
-
25 ft3
-
50 ft3
-
75 ft3
-
100 ft3
Questão 19
Questão
combustion air may be added to a confined space by a duct to the outside, sized on an input of 1 in2 per __________.
Responda
-
1000 btu
-
2000 btu
-
4000 btu
-
5000 btu
Questão 20
Questão
what type of burners are commonly used with induced-draft gas furnaces?
Responda
-
gun style
-
pot style
-
ribbon
-
inshot
Questão 21
Questão
what is the typical color of a properly burning gas flame?
Responda
-
blue
-
orange
-
red
-
yellow
Questão 22
Questão
in a gas furnace, primary combustion air is introduced in the ________.
Responda
-
burner prior to ignition
-
burner after ignition
-
gas line
-
heat exchanger
Questão 23
Questão
a "dumbbell" style CO2 tester ___________.
Responda
-
contains a test fluid that absorbs CO2
-
measures CO2 in parts per million
-
provides a digital readout
-
requires a power supply
Questão 24
Questão
useful heat output, expressed as a percentage of the total burner input, is known as the ________ of a gas furnace.
Responda
-
combustion efficiency
-
fuel efficiency
-
heat exchanger performance factor
-
heating coerfficient
Questão 25
Questão
which type of ignition system uses a thermocouple?
Responda
-
direct ignition
-
hot surface
-
intermittent ignition
-
standing pilot
Questão 26
Questão
the blower in a standing pilot furnace is generally started by a(n) __________.
Responda
-
differential pressure switch
-
ignition module
-
temperature switch
-
time-delay relay
Questão 27
Questão
a furnace with an induced draft fan uses a ________. to prove air flow
Responda
-
high pressure switch
-
lower pressure switch
-
pressure differential switch
-
sail switch
Questão 28
Questão
flame rectification proves flame by creating a signal in response to a ________.
Responda
-
change in resistance
-
current conducted in one direction through the flame
-
temperature activated switch
-
voltage produced by the flame
Questão 29
Questão
when the output of a furnace matches the heat loss or heat gain of the conditioned space, the system is said to be at its
Responda
-
balanced point
-
design temperature
-
full-load condition
-
reference point
Questão 30
Questão
residential load calculations should be completed according to ACCA's
Responda
-
manual D
-
Manual J
-
Manual N
-
Manual P
Questão 31
Questão
when furnaces are installed in attics or crawl spaces, special care must be taken to__________.
Responda
-
distribute weight properly
-
insulate the ductwork
-
protect water lines from freezing
-
all of the above
Questão 32
Questão
which of the following is true of low voltage control wiring.
Responda
-
it is exempt from NEC requirments
-
it may not be run in the same conduit as line voltage
-
it may not exceed 100ft in length
-
it must be ran in metal conduit
Questão 33
Questão
what is the maximum pressure that can be supplied to most natural gas furnaces?
Responda
-
3.5 in W.C.
-
14 in W.C.
-
2 psi
-
5 psi
Questão 34
Questão
the sensor of an electronic leak detector can be affected by ________. which may cause the instrument to give a false indication of a gas leak
Responda
-
cutting oil
-
moisture
-
pipe sealant
-
teflon tape
Questão 35
Questão
what is the minimum diameter for condensate drain pipe
Responda
-
1/2 in
-
3/4 in
-
1 in
-
1 1/4 in
Questão 36
Questão
generally speaking a residential thermostat should be mounted _________.
Responda
-
approximately 5 ft off the floor
-
in the kitchen
-
near a supply register
-
on an exterior wall
Questão 37
Questão
which is the proper terminal for heating on most thermostats
Responda
-
C
-
G
-
W
-
Y
-
B
-
H
Questão 38
Questão
on an auto changeover thermostat, the difference between heating and cooling setpoints (that keeps the equipment cycling back and forth between heating and cooling) is know as the ________.
Responda
-
deadband
-
droop
-
offset
-
throttling range
Questão 39
Questão
in order to prevent condensation from forming in the heat exchanger, the cooling coil should always be mounted ________.
Responda
-
from behind :-)
-
before the heat exchanger
-
below the heat exchanger
-
downstream from the heat exchanger
-
upstream from the heat exchanger
Questão 40
Questão
in the summer months, the damper on the bypass humidifier should be _________.
Responda
-
fully closed
-
fully open
-
partially open
-
removed
Questão 41
Questão
which of the following is NOT true of a residential zoned system
Responda
-
each zone has its own temperature control
-
there can be no more then four zones
-
zoned units may use a by pass damper to pass excess supply air back into return air
-
zoned units may use a dump damper to pass excess supply air to a non-critical area
Questão 42
Questão
a type of equipment that transfers both latent and sensible heat from the exhaust air to the supply air is know as a(n) ________.
Responda
-
economizer
-
energy recovery ventilator
-
fresh air intake
-
heat recovery ventilator
Questão 43
Questão
a standing pilot furnace with an atmospheric burner is an example of a __________ gas appliance
Responda
-
category I
-
category II
-
category III
-
category IV
Questão 44
Questão
a high efficiency condensing furnace is an example of a _________ gas appliance
Responda
-
category I
-
category II
-
Category III
-
category IV
Questão 45
Questão
burning of 1 ft3 of natural gas produces __________ of flue gas
Responda
-
1 ft3
-
2 ft3
-
10 ft3
-
11 ft3
Questão 46
Questão
which of the following affects the venting force in a gravity venting system
Responda
-
the height of the chimney
-
the percentage of CO2 in the flue gas
-
the type of fuel used
-
the type of fuel pipe used
Questão 47
Questão
a fan is used to pull flue gases through the combustion chamber in a(n) _________ vent system.
Responda
-
forced draft
-
gravity
-
induced draft
-
natural draft
Questão 48
Questão
how far above the peak of the roof should the chimney extend
Responda
-
1 ft
-
2 ft
-
3 ft
-
4 ft
Questão 49
Questão
a horizontal flue vent must have an upward slope of at least _________ per foot of length.
Responda
-
1/8 in
-
1/4 in
-
1/2 in
-
1 in
Questão 50
Questão
problems related to a shortage or contamination of combustion air are eliminated in a(n) vent system
Responda
-
direct
-
forced draft
-
gravity
-
induced draft
Questão 51
Questão
when can a masonry chimney be used to vent category IV appliances?
Responda
-
when it is existing chimney
-
when it is no more that one story tall
-
when it is used as a common vent along with a category I appliance
-
Never
Questão 52
Questão
category IV furnaces are commonly vented with what type of material
Responda
-
single wall metal
-
double wall class B
-
masonry
-
PVC pine
Questão 53
Questão
when does a category IV vent pipe require insulation?
Responda
-
always
-
never
-
only when the vent pipe runs outdoors
-
when the length of the vent pipe running through an unconditioned space exceeds the length listed in the manufacturers tables.
Questão 54
Questão
category IV equipment required a condensate drain. a trap must be installed in the drain line to _________.
Responda
-
break the vacuum allowing water to drain
-
keep water from draining to quickly
-
prevent water from freezing
-
provide a seal that prevents the leakage of flue gas
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