David Brown
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HVAC Quiz on Gas and Oil Heating Exam, created by David Brown on 16/07/2018.

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David Brown
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Gas and Oil Heating Exam

Question 1 of 54

1

in a modern gas furnace, the component that separates the combustion gases from the supply air is the __________.

Select one of the following:

  • gas valve

  • heat exchanger

  • inducer fan

  • plenum box

Explanation

Question 2 of 54

1

what type of furnace moves warm air through the conditioned space without a fan?

Select one of the following:

  • gravity

  • horizontal

  • lowboy

  • upflow

Explanation

Question 3 of 54

1

furnace heat exchangers generally are made of ___________.

Select one of the following:

  • ceramic

  • copper

  • plastic

  • steel

Explanation

Question 4 of 54

1

what does AFUE stand for?

Select one of the following:

  • actual fuel usage efficiency

  • annual fuel utilization efficiency

  • annual furnace usage equivalency

  • approved fuel usage estimate

Explanation

Question 5 of 54

1

the main purpose of a secondary heat exchanger is to _________.

Select one of the following:

  • evaporate the flue gases

  • provide a backup containment

  • remove additional heat from the flue gases

  • reverse the primary air flow

Explanation

Question 6 of 54

1

which gas commonly used as a fuel in gas furnaces is heavier than air?

Select one of the following:

  • butane

  • isobutene

  • methane

  • propane

Explanation

Question 7 of 54

1

which grade of fuel oil is commonly used in residential furnaces

Select one of the following:

  • 1

  • 2

  • 3

  • 4

Explanation

Question 8 of 54

1

how many cubic feet of air are needed to burn 1 ft3 of natural gas

Select one of the following:

  • 6

  • 10

  • 18

  • 24

Explanation

Question 9 of 54

1

how many cubic feet of air are needed to burn 1 ft3 of propane

Select one of the following:

  • 6

  • 10

  • 18

  • 24

Explanation

Question 10 of 54

1

what is the approximate heat content of 1 ft3 of natural gas?

Select one of the following:

  • 500 btu

  • 800 btu

  • 1050 btu

  • 2500 btu

Explanation

Question 11 of 54

1

what is the approximate heat content of 1 ft3 of propane

Select one of the following:

  • 500 btu

  • 800 btu

  • 1050 btu

  • 2500 btu

Explanation

Question 12 of 54

1

what is the approximate heat content of one gallon of No.2 fuel oil?

Select one of the following:

  • 75,000 to 90,000 btu

  • 95,000 to 135,000 btu

  • 137,000 to 142,000 btu

  • 145,000 to 170,000 btu

Explanation

Question 13 of 54

1

what is a typical manifold pressure for a natural gas furnace?

Select one of the following:

  • 3.5 in w.c.

  • 11 in w.c.

  • 2 psi

  • 5 psi

Explanation

Question 14 of 54

1

what is the typical atmospheric manifold pressure for a propane furnace?

Select one of the following:

  • 3.5 in w.c.

  • 11 in w.c.

  • 2 psi

  • 5 psi

Explanation

Question 15 of 54

1

what type of furnace is commonly installed in a closet with underfloor supply ducts?

Select one of the following:

  • downflow

  • horizontal

  • lowboy

  • upflow

Explanation

Question 16 of 54

1

which of the following is required for combustion?

Select one of the following:

  • fuel

  • heat

  • oxygen

  • all of the above

Explanation

Question 17 of 54

1

which of the following is not a product of complete combustion?

Select one of the following:

  • carbon dioxide

  • carbon monoxide

  • heat

  • water

Explanation

Question 18 of 54

1

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

Select one of the following:

  • 25 ft3

  • 50 ft3

  • 75 ft3

  • 100 ft3

Explanation

Question 19 of 54

1

combustion air may be added to a confined space by a duct to the outside, sized on an input of 1 in2 per __________.

Select one of the following:

  • 1000 btu

  • 2000 btu

  • 4000 btu

  • 5000 btu

Explanation

Question 20 of 54

1

what type of burners are commonly used with induced-draft gas furnaces?

Select one of the following:

  • gun style

  • pot style

  • ribbon

  • inshot

Explanation

Question 21 of 54

1

what is the typical color of a properly burning gas flame?

Select one of the following:

  • blue

  • orange

  • red

  • yellow

Explanation

Question 22 of 54

1

in a gas furnace, primary combustion air is introduced in the ________.

Select one of the following:

  • burner prior to ignition

  • burner after ignition

  • gas line

  • heat exchanger

Explanation

Question 23 of 54

1

a "dumbbell" style CO2 tester ___________.

Select one of the following:

  • contains a test fluid that absorbs CO2

  • measures CO2 in parts per million

  • provides a digital readout

  • requires a power supply

Explanation

Question 24 of 54

1

useful heat output, expressed as a percentage of the total burner input, is known as the ________ of a gas furnace.

Select one of the following:

  • combustion efficiency

  • fuel efficiency

  • heat exchanger performance factor

  • heating coerfficient

Explanation

Question 25 of 54

1

which type of ignition system uses a thermocouple?

Select one of the following:

  • direct ignition

  • hot surface

  • intermittent ignition

  • standing pilot

Explanation

Question 26 of 54

1

the blower in a standing pilot furnace is generally started by a(n) __________.

Select one of the following:

  • differential pressure switch

  • ignition module

  • temperature switch

  • time-delay relay

Explanation

Question 27 of 54

1

a furnace with an induced draft fan uses a ________. to prove air flow

Select one of the following:

  • high pressure switch

  • lower pressure switch

  • pressure differential switch

  • sail switch

Explanation

Question 28 of 54

1

flame rectification proves flame by creating a signal in response to a ________.

Select one of the following:

  • change in resistance

  • current conducted in one direction through the flame

  • temperature activated switch

  • voltage produced by the flame

Explanation

Question 29 of 54

1

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

Select one of the following:

  • balanced point

  • design temperature

  • full-load condition

  • reference point

Explanation

Question 30 of 54

1

residential load calculations should be completed according to ACCA's

Select one of the following:

  • manual D

  • Manual J

  • Manual N

  • Manual P

Explanation

Question 31 of 54

1

when furnaces are installed in attics or crawl spaces, special care must be taken to__________.

Select one of the following:

  • distribute weight properly

  • insulate the ductwork

  • protect water lines from freezing

  • all of the above

Explanation

Question 32 of 54

1

which of the following is true of low voltage control wiring.

Select one of the following:

  • 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

Explanation

Question 33 of 54

1

what is the maximum pressure that can be supplied to most natural gas furnaces?

Select one of the following:

  • 3.5 in W.C.

  • 14 in W.C.

  • 2 psi

  • 5 psi

Explanation

Question 34 of 54

1

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

Select one of the following:

  • cutting oil

  • moisture

  • pipe sealant

  • teflon tape

Explanation

Question 35 of 54

1

what is the minimum diameter for condensate drain pipe

Select one of the following:

  • 1/2 in

  • 3/4 in

  • 1 in

  • 1 1/4 in

Explanation

Question 36 of 54

1

generally speaking a residential thermostat should be mounted _________.

Select one of the following:

  • approximately 5 ft off the floor

  • in the kitchen

  • near a supply register

  • on an exterior wall

Explanation

Question 37 of 54

1

which is the proper terminal for heating on most thermostats

Select one of the following:

  • C

  • G

  • W

  • Y

  • B

  • H

Explanation

Question 38 of 54

1

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 ________.

Select one of the following:

  • deadband

  • droop

  • offset

  • throttling range

Explanation

Question 39 of 54

1

in order to prevent condensation from forming in the heat exchanger, the cooling coil should always be mounted ________.

Select one of the following:

  • from behind :-)

  • before the heat exchanger

  • below the heat exchanger

  • downstream from the heat exchanger

  • upstream from the heat exchanger

Explanation

Question 40 of 54

1

in the summer months, the damper on the bypass humidifier should be _________.

Select one of the following:

  • fully closed

  • fully open

  • partially open

  • removed

Explanation

Question 41 of 54

1

which of the following is NOT true of a residential zoned system

Select one of the following:

  • 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

Explanation

Question 42 of 54

1

a type of equipment that transfers both latent and sensible heat from the exhaust air to the supply air is know as a(n) ________.

Select one of the following:

  • economizer

  • energy recovery ventilator

  • fresh air intake

  • heat recovery ventilator

Explanation

Question 43 of 54

1

a standing pilot furnace with an atmospheric burner is an example of a __________ gas appliance

Select one of the following:

  • category I

  • category II

  • category III

  • category IV

Explanation

Question 44 of 54

1

a high efficiency condensing furnace is an example of a _________ gas appliance

Select one of the following:

  • category I

  • category II

  • Category III

  • category IV

Explanation

Question 45 of 54

1

burning of 1 ft3 of natural gas produces __________ of flue gas

Select one of the following:

  • 1 ft3

  • 2 ft3

  • 10 ft3

  • 11 ft3

Explanation

Question 46 of 54

1

which of the following affects the venting force in a gravity venting system

Select one of the following:

  • the height of the chimney

  • the percentage of CO2 in the flue gas

  • the type of fuel used

  • the type of fuel pipe used

Explanation

Question 47 of 54

1

a fan is used to pull flue gases through the combustion chamber in a(n) _________ vent system.

Select one of the following:

  • forced draft

  • gravity

  • induced draft

  • natural draft

Explanation

Question 48 of 54

1

how far above the peak of the roof should the chimney extend

Select one of the following:

  • 1 ft

  • 2 ft

  • 3 ft

  • 4 ft

Explanation

Question 49 of 54

1

a horizontal flue vent must have an upward slope of at least _________ per foot of length.

Select one of the following:

  • 1/8 in

  • 1/4 in

  • 1/2 in

  • 1 in

Explanation

Question 50 of 54

1

problems related to a shortage or contamination of combustion air are eliminated in a(n) vent system

Select one of the following:

  • direct

  • forced draft

  • gravity

  • induced draft

Explanation

Question 51 of 54

1

when can a masonry chimney be used to vent category IV appliances?

Select one of the following:

  • 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

Explanation

Question 52 of 54

1

category IV furnaces are commonly vented with what type of material

Select one of the following:

  • single wall metal

  • double wall class B

  • masonry

  • PVC pine

Explanation

Question 53 of 54

1

when does a category IV vent pipe require insulation?

Select one of the following:

  • 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.

Explanation

Question 54 of 54

1

category IV equipment required a condensate drain. a trap must be installed in the drain line to _________.

Select one of the following:

  • 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

Explanation

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