Frage 1
Frage
in a modern gas furnace, the component that separates the combustion gases from the supply air is the __________.
Antworten
-
gas valve
-
heat exchanger
-
inducer fan
-
plenum box
Frage 2
Frage
what type of furnace moves warm air through the conditioned space without a fan?
Antworten
-
gravity
-
horizontal
-
lowboy
-
upflow
Frage 3
Frage
furnace heat exchangers generally are made of ___________.
Antworten
-
ceramic
-
copper
-
plastic
-
steel
Frage 4
Frage
what does AFUE stand for?
Antworten
-
actual fuel usage efficiency
-
annual fuel utilization efficiency
-
annual furnace usage equivalency
-
approved fuel usage estimate
Frage 5
Frage
the main purpose of a secondary heat exchanger is to _________.
Antworten
-
evaporate the flue gases
-
provide a backup containment
-
remove additional heat from the flue gases
-
reverse the primary air flow
Frage 6
Frage
which gas commonly used as a fuel in gas furnaces is heavier than air?
Antworten
-
butane
-
isobutene
-
methane
-
propane
Frage 7
Frage
which grade of fuel oil is commonly used in residential furnaces
Frage 8
Frage
how many cubic feet of air are needed to burn 1 ft3 of natural gas
Frage 9
Frage
how many cubic feet of air are needed to burn 1 ft3 of propane
Frage 10
Frage
what is the approximate heat content of 1 ft3 of natural gas?
Antworten
-
500 btu
-
800 btu
-
1050 btu
-
2500 btu
Frage 11
Frage
what is the approximate heat content of 1 ft3 of propane
Antworten
-
500 btu
-
800 btu
-
1050 btu
-
2500 btu
Frage 12
Frage
what is the approximate heat content of one gallon of No.2 fuel oil?
Antworten
-
75,000 to 90,000 btu
-
95,000 to 135,000 btu
-
137,000 to 142,000 btu
-
145,000 to 170,000 btu
Frage 13
Frage
what is a typical manifold pressure for a natural gas furnace?
Antworten
-
3.5 in w.c.
-
11 in w.c.
-
2 psi
-
5 psi
Frage 14
Frage
what is the typical atmospheric manifold pressure for a propane furnace?
Antworten
-
3.5 in w.c.
-
11 in w.c.
-
2 psi
-
5 psi
Frage 15
Frage
what type of furnace is commonly installed in a closet with underfloor supply ducts?
Antworten
-
downflow
-
horizontal
-
lowboy
-
upflow
Frage 16
Frage
which of the following is required for combustion?
Antworten
-
fuel
-
heat
-
oxygen
-
all of the above
Frage 17
Frage
which of the following is not a product of complete combustion?
Antworten
-
carbon dioxide
-
carbon monoxide
-
heat
-
water
Frage 18
Frage
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
Antworten
-
25 ft3
-
50 ft3
-
75 ft3
-
100 ft3
Frage 19
Frage
combustion air may be added to a confined space by a duct to the outside, sized on an input of 1 in2 per __________.
Antworten
-
1000 btu
-
2000 btu
-
4000 btu
-
5000 btu
Frage 20
Frage
what type of burners are commonly used with induced-draft gas furnaces?
Antworten
-
gun style
-
pot style
-
ribbon
-
inshot
Frage 21
Frage
what is the typical color of a properly burning gas flame?
Frage 22
Frage
in a gas furnace, primary combustion air is introduced in the ________.
Antworten
-
burner prior to ignition
-
burner after ignition
-
gas line
-
heat exchanger
Frage 23
Frage
a "dumbbell" style CO2 tester ___________.
Antworten
-
contains a test fluid that absorbs CO2
-
measures CO2 in parts per million
-
provides a digital readout
-
requires a power supply
Frage 24
Frage
useful heat output, expressed as a percentage of the total burner input, is known as the ________ of a gas furnace.
Frage 25
Frage
which type of ignition system uses a thermocouple?
Antworten
-
direct ignition
-
hot surface
-
intermittent ignition
-
standing pilot
Frage 26
Frage
the blower in a standing pilot furnace is generally started by a(n) __________.
Frage 27
Frage
a furnace with an induced draft fan uses a ________. to prove air flow
Frage 28
Frage
flame rectification proves flame by creating a signal in response to a ________.
Antworten
-
change in resistance
-
current conducted in one direction through the flame
-
temperature activated switch
-
voltage produced by the flame
Frage 29
Frage
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
Antworten
-
balanced point
-
design temperature
-
full-load condition
-
reference point
Frage 30
Frage
residential load calculations should be completed according to ACCA's
Antworten
-
manual D
-
Manual J
-
Manual N
-
Manual P
Frage 31
Frage
when furnaces are installed in attics or crawl spaces, special care must be taken to__________.
Frage 32
Frage
which of the following is true of low voltage control wiring.
Antworten
-
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
Frage 33
Frage
what is the maximum pressure that can be supplied to most natural gas furnaces?
Antworten
-
3.5 in W.C.
-
14 in W.C.
-
2 psi
-
5 psi
Frage 34
Frage
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
Antworten
-
cutting oil
-
moisture
-
pipe sealant
-
teflon tape
Frage 35
Frage
what is the minimum diameter for condensate drain pipe
Antworten
-
1/2 in
-
3/4 in
-
1 in
-
1 1/4 in
Frage 36
Frage
generally speaking a residential thermostat should be mounted _________.
Frage 37
Frage
which is the proper terminal for heating on most thermostats
Frage 38
Frage
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 ________.
Antworten
-
deadband
-
droop
-
offset
-
throttling range
Frage 39
Frage
in order to prevent condensation from forming in the heat exchanger, the cooling coil should always be mounted ________.
Antworten
-
from behind :-)
-
before the heat exchanger
-
below the heat exchanger
-
downstream from the heat exchanger
-
upstream from the heat exchanger
Frage 40
Frage
in the summer months, the damper on the bypass humidifier should be _________.
Antworten
-
fully closed
-
fully open
-
partially open
-
removed
Frage 41
Frage
which of the following is NOT true of a residential zoned system
Antworten
-
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
Frage 42
Frage
a type of equipment that transfers both latent and sensible heat from the exhaust air to the supply air is know as a(n) ________.
Frage 43
Frage
a standing pilot furnace with an atmospheric burner is an example of a __________ gas appliance
Antworten
-
category I
-
category II
-
category III
-
category IV
Frage 44
Frage
a high efficiency condensing furnace is an example of a _________ gas appliance
Antworten
-
category I
-
category II
-
Category III
-
category IV
Frage 45
Frage
burning of 1 ft3 of natural gas produces __________ of flue gas
Antworten
-
1 ft3
-
2 ft3
-
10 ft3
-
11 ft3
Frage 46
Frage
which of the following affects the venting force in a gravity venting system
Antworten
-
the height of the chimney
-
the percentage of CO2 in the flue gas
-
the type of fuel used
-
the type of fuel pipe used
Frage 47
Frage
a fan is used to pull flue gases through the combustion chamber in a(n) _________ vent system.
Antworten
-
forced draft
-
gravity
-
induced draft
-
natural draft
Frage 48
Frage
how far above the peak of the roof should the chimney extend
Frage 49
Frage
a horizontal flue vent must have an upward slope of at least _________ per foot of length.
Antworten
-
1/8 in
-
1/4 in
-
1/2 in
-
1 in
Frage 50
Frage
problems related to a shortage or contamination of combustion air are eliminated in a(n) vent system
Antworten
-
direct
-
forced draft
-
gravity
-
induced draft
Frage 51
Frage
when can a masonry chimney be used to vent category IV appliances?
Antworten
-
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
Frage 52
Frage
category IV furnaces are commonly vented with what type of material
Antworten
-
single wall metal
-
double wall class B
-
masonry
-
PVC pine
Frage 53
Frage
when does a category IV vent pipe require insulation?
Frage 54
Frage
category IV equipment required a condensate drain. a trap must be installed in the drain line to _________.
Antworten
-
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