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WorksheetsACR-205 Final Exam with Components
Total questions: 140
Worksheet time: 2hrs 42mins
Label the Picture
Inducer Fan
Gas Burner
Condensate Drain
Electric Blower Motor
Cold Air Return
Air Filter
Circulating Fan
Heat Exchanger
Heater Air To Home
Flue Gas Exhaust Vent
What happens when the thermostat reaches a set temperature or is turned up by the homeowner?
The gas valve opens
The furnace ignitor glows
The thermostat sends a signal for the furnace to turn on
The blower motor starts
What voltage should you measure between W and C on the control board during the safety check?
12 volts AC
24 volts AC
110 volts AC
125 volts AC
What is the function of the inducer motor in the furnace operation sequence?
To open the gas valve
To create a vacuum to ensure leftover gases go out the exhaust pipe
To ignite the furnace
To start the blower motor
What happens if the pressure switch does not close?
The gas valve opens
The furnace ignitor glows
The inducer motor stops
The furnace will not proceed to the next step
What should the furnace ignitor do when the control board sends power to it?
Open the gas valve
Start the blower motor
Glow bright orange
Close the pressure switch
What ensures proper combustion in the furnace?
The blower motor
The gas valve opening and combining gas with air
The furnace ignitor
The pressure switch closing
What will the flame sensor do if the gas burners do not ignite within 5 to 8 seconds?
Keep the gas valve open
Turn the ignition source off
Start the blower motor
Close the pressure switch
What happens after a pre-determined amount of time when the blower motor starts?
The gas valve opens
The furnace ignitor glows
Air is passed over the system's heat exchangers to provide heated air
The thermostat sends a signal for the furnace to turn on
What happens when the thermostat on the wall satisfies the need for heat?
The gas valve opens
The blower motor starts
The voltage in the W wire is broken and the gas burners are cut off
The furnace ignitor glows
What does the furnace blower motor do after the heat is removed from the furnace's heat exchanger?
It continues to run for a set amount of time
It shuts down immediately
It starts the furnace ignitor
It opens the gas valve
A furnace with a vertical air flow through the heat exchanger and the blower compartment beneath the heat exchanger is called a(n) _____.
upflow
downflow
low boy
Horizontal
The orifice is a precisely sized hole in the _____.
manifold
spud
burner tube
combustion chamber
Most gas furnaces and appliances use a(n) _____ burner.
compressed
hybrid
pressurized
Atmospheric
The proper color of a gas flame is ____.
sharp all blue
lazy all blue
blue with slight orange tips
lazy with yellow tips
A condensing gas furnace uses ____ from a condensing type heat exchanger to increase the furnace efficiency.
sensible heat
latent heat
superheat
Subcooling
In a conventional gas furnace, the hot flue gases are ____.
forced out a PVC vent with a blower
recycled through a secondary heat exchanger and then vented through a draft diverter
forced through a type B vent by a blower
vented by natural convection
Primary air adjusters on atmospheric type gas burners are usually ____.
butterfly shutters
sliding sleeves
spoiler screws
all of the above
Liquefied petroleum (LP) is heavier than air and can cause suffocation if not handled properly.
True
False
A gas furnace designed for use with natural gas can be used with liquefied petroleum (LP) with no system modifications.
True
False
In the USA, natural gas suppliers supply gas with a heat content of about 1,050 Btu/cu. ft.
True
False
If flue gases are not vented properly, carbon monoxide poisoning could result.
True
False
The gas flame will lift off the burner and be noisy if it receives too much primary air.
True
False
Another name for a downflow heating unit is (a) .
The horizontal furnace is positioned on its side, and it is usually installed in locations where it takes (a) .
Three products of complete combustion of natural and LP gas are carbon dioxide, water vapor, and (a) .
The dangerous by-product of poor combustion of gas is (a) .
Spark ignition is important for roof top or package units located outdoors because of (a) .
Butterfly shutters and sliding sleeves are examples of (a) and are used on atmospheric type gas burners.
Why is "inches of water column" used to measure gas pressure instead of psig?
"Inches of air column" is a smaller scale for lower pressures, like manifold pressures.
"Inches of liquid column" is a smaller scale for lower pressures, like manifold pressures.
"Inches of water column" is a smaller scale for higherr pressures, like manifold pressures.
What is the difference between a yellow gas flame and an orange gas flame?
The flame in a gas fired furnace is burning with heavy yellow tips. What is the problem?
While the furnace is operating, heated air and flue products spill out of the burner compartment. What is the problem?
Why do propane and butane gas furnaces require 100% shut off in the event of pilot outage?
On a gas furnace, what energizes the blower motor in the heat mode?
When a gas furnace ignites and is under "full-fire," why does the fan not come on immediately?
When the burners ignite, the burner flame is normal until the blower starts. At this time, continuous roll out occurs. What is the problem?
Generally speaking, electric heat is very efficient but can be more expensive to operate compared to oil and gas.
True
False
Some units may be designed to move enough air across the heating elements so that they do not glow.
True
False
One potential safety hazard that all technicians should be aware of when working on an electric furnace is that there are many exposed electrical connections behind the inspection panels.
True
False
Electric heating units provide almost instant heat. Therefore, anticipators are not needed in electric heat thermostats.
True
False
If the number two contact on a package sequencer fails to close, the number three contact can still close.
True
False
Where in a room are electric baseboard heaters normally placed?
They are mounted on the wall just above the floor or carpet, usually on outside walls.
They are mounted on the wall just above the window or carpet, usually on outside walls.
They are mounted on the floor just above the floor or carpet, usually on outside walls.
They are mounted on the wall just above the floor or carpet, usually on inside walls.
In order to prevent a duct-mounted electric heater from being energized when the fan is not on, a(n) (a) should be used.
A set of contacts actuated by a bimetal strip with a low-voltage wire wrapped around it is called a(n) (a) .
In order to provide time delay between stages of electric heat, the controls that are used are called (a) .
Radiant electric heating panels used for ceiling installation are often made of (a) with wire heating circuits running throughout.
For each watt of electrical power, (a) Btu/h are generated.
How should you determine the heat anticipator setting on a room thermostat?
The setting is determined by the total current draw in the 24-V heating circuit that passes through the thermostat control and heat anticipator.
The setting is determined by the total current draw in the 12-V heating circuit that passes through the thermostat control and heat anticipator.
The setting is determined by the total current draw in the 240-V heating circuit that passes through the thermostat control and heat anticipator.
The setting is determined by the total current draw in the 120-V heating circuit that passes through the thermostat control and heat anticipator.
Why do most electric furnaces have several heating elements that are activated in stages?
To avoid energizing a high power load all at once.
To avoid de-energizing a high power load all at once.
To avoid energizing a low-power load all at once.
To activate energizing a high power load all at once.
A pictorial diagram shows component location, while a schematic shows the current paths to the components.
True
False
Where are unit and wall electric heaters typically mounted?
They are typically mounted on ceilings or walls and use a fan to force the air across the elements into the space to be heated.
They are typically mounted below ceilings or walls and use a fan to force the air across the elements into the space to be heated.
They are typically mounted on ceilings or floors and use a fan to force the air across the elements into the space to be heated.
They are typically mounted on ceilings or walls and use a fan to force the air across the elements into the space to be cooled.
Why aren't contactors used in residential and small commercial electric heating units?
Their operating noise is too high.
Their operating cost is too high.
Their operating noise is too low.
None are correct
Radiant heat is transferred by ____.
ultraviolet rays
infrared rays
ionization
refraction
All electric furnaces use package sequencers.
True
False
Electric baseboard heaters are classified as ____.
natural-convection heaters
forced-convection heaters
forced-draft conductors
radiant heaters
The resistance wire used in electric heating elements is usually ____.
copper
nickel steel
nickel chromium
aluminum
The limit switch is used on the electric element assembly to ____.
start the unit if the thermostat malfunctions
ensure that the fan stops when the unit cools down
start the unit prematurely on a cold day
shuts off the unit if high temperature occurs
The benefits of electric baseboard heating are that ____.
each room can be controlled individually
they are inexpensive to install
they operate on a 24-V power supply
Both a and b.
An electric heating unit that utilizes ductwork to distribute the heated air is classified as a ____.
natural-convection heater
forced-convection heater
forced-draft conductor
radiant heater
Which of the following elements is not a power-consuming device?
The sequencer heater coil.
A magnetic solenoid that moves the armature in a contactor.
The contacts of a contactor.
The blower motor.
If the number two contact on a package sequencer fails to close, the number three contact can still close.
True
False
Any unit heater designed to have air forced across the element should not be operated without the ____ operating.
fuse
interlock
element
fan
Quartz and glass panel electric units are classified as ____.
natural-convection heaters
forced-convection heaters
forced-draft conductors
radiant heaters
A 10 Kw heating element, operating on rated 240 V, will generate ____ Btu/h.
29,319
31,062
34,130
35,875
The expansion tank provides a means of removing the air from the system as well as provides ____.
a space for excess water from the supply source
water for the domestic hot water coil
a space for the water expansion and contraction with water temperature changes
All of the above.
A column of water 1 ft high exerts a pressure of ____.
0.277 psig
0.299 psig
0.433 psig
14.696 psig
The more common type of expansion tank is the ____ expansion tank.
compression
standard
restricted
diaphragm-type
The reason for using zone valves on a hydronic heating system is to ____.
allow different areas of the structure to maintain different temperatures
reduce the chance of a water leak
prevent unused parts of the house from getting warm, and wasting energy
Both a and c.
Air in a hydronic system can cause ____.
reduced water circulation
increased water concentration
corrosion
Both a and c.
A pressure relief valve is set at 30 psig. The valve is constantly opening and flooding the floor. What is causing the relief valve to constantly open?
The water-regulating valve is broken.
The system is overfiring.
The system needs to be calibrated.
The system requires a new boiler.
A high-limit control on a hot water boiler is needed to ________.
regulate the amount of water to each section of baseboard
regulate the water in the supply line to the boiler
balance the water flow rate in the piping system
protect the boiler against excessive water temperatures
The pressure relief valve ________.
regulates the pressure of the water in the supply line
is set to relieve the pressure in the boiler below its maximum design pressure
shuts the boiler off if the water temperature gets too high
relieves the pressure in the expansion tank
An expansion joint is a device used to ________.
prevent damage between boiler sections
enlarge the expansion tank in the system
allow for expansion and contraction of the loop piping with water temperature changes
connect the manual vent into the system
A series loop hydronic system is not desirable for use in a large residence because ____.
all of the heated water will flow to all rooms
some rooms will overheat before other rooms are warm
it is difficult to install and maintain
Both a and b.
The series loop system is the hydronic system that is found most often, primarily because of the ____.
heated water flows in the same direction in parallel pipes
first terminal units being supplied will be warmer than the later ones
possibility of having individual temperature control for each area being heated
low installation costs
The more sections a boiler has, the higher its capacity will be.
True
False
Expansion tanks must always be bled from the top until all of the air is removed from it.
True
False
Hydronic heat circulators are centrifugal pumps.
True
False
Automatic air vents rely on an internal disc that swells when water is sensed.
True
False
It is important to note that the air separator does not remove air from the system.
True
False
The only place a bleed valve is needed is on top of the boiler.
True
False
In a series loop, the water going through the last terminal unit will be the same temperature as the water through the first terminal unit.
True
False
A tankless domestic water system provides hot water from a coil in the boiler.
True
False
Hydronic heating systems are systems in which water or (a) carries the heat through pipes to the areas to be heated.
In hot water hydronic systems, water is heated and circulated through pipes to a heat transfer component called a terminal unit.
True
False
The vanes of the impellers used in circulating pumps in hot water heating systems are usually enclosed, and are referred to as (a) impellers.
Pumps generally have a cast-iron body with the impeller and other moving parts made of (a) or nonferrous metals.
The high-limit control, like the (a) , is a device that opens and closes its contacts in response to boiler water temperature.
Most residences with modern hydronic heating systems use (a) baseboard heat transfer for terminal heating units.
Zone control valves are controlled by (a) .
On systems that use two-port zone valves, excessive pressure in the supply header may result when multiple zone valves (a) .
The low-water (a) valve is responsible for deenergizing the hydronic system in the event the level of water in the system drops below the desired point.
An automatic air vent controls the airflow out of the system by means of a(n) (a) , which rises and falls with the amount of air in the system.
The grade of fuel used in residential and light commercial units is ____.
Number 1
Number 2
Number 4
Number 6
When the oil tank is above the oil burner pump, the fuel oil supply system would normally be a ____.
gravity flow, one-pipe system
single-stage pump, two-pipe system
two-stage pump, one-pipe system
two-stage pump, two-pipe system
An auxiliary tank and booster pump system is required if the oil supply is situated ____ below the oil burner pump.
any distance
5 feet or more
10 feet or more
15 feet or more
If a technician inspects the interior of a combustion chamber and finds large quantities of unburned oil, he would correctly conclude that the stack switch, cad cell may be defective and/or the primary control unit may be defective.
True
False
When nozzles problems are apparent, the nozzle should be removed using ____ and replaced.
a. a special nozzle wrench
b. adjustable pliers
c. a pipe wrench
d. Both a and b.
The cad cell relay is a safety device that uses which of the following to prove ignition?
a. Heat in the flue
b. Heat in the combustion chamber
c. Light in the combustion chamber
d. Heat in the blast tube.
The stack switch or stack relay ____.
a. starts the fan motor when the thermostat calls for heat
b. shuts down the burner if it does not sense heat in the stack
c. cuts off the ignition after the flame has been established
d. All of the above.
A condensing oil furnace operates at a higher efficiency because part of the heat output is ____.
sensible heat
latent heat
superheat
sub-cooling
Improper combustion can lead to ____.
excessive carbon monoxide production
smoke condition around furnace
wasted fuel oil
All of the above.
To make combustion efficiency tests, a hole must be made ____.
in the flue pipe after the draft control
in the flue pipe before the draft control
over the fire at the observation door
under the draft hood
Oil tanks should be checked for water at least once a month.
True
False
Tanks that are to be installed underground must be protected against corrosion.
True
False
Tank piping should be inspected regularly for imperfections and leaks.
True
False
In a single-stage fuel oil pump, the oil is fed to the burner by capillary action.
True
False
Oil burner nozzles are rated at 100 psig nozzle pressure.
True
False
Nozzles can be cleaned to remove any carbonization by using a very fine wire brush.
True
False
When any product containing hydrogen and/or carbon reacts with oxygen to release heat energy, the process is called (a) .
The heat content of one gallon of No. 2 fuel oil is about (a) Btu.
(a) is the amount of carbon left in a sample of oil after it is changed from a liquid to a vapor by being boiled in an oxygen-free atmosphere.
In a(n) (a) fuel oil supply system, one pipe is the supply and the other acts as the return.
Oil lines are typically made of copper and should be sized at a minimum (a) OD.
Fill and (a) pipes should be pitched toward the tank opening to prevent the formation of oil traps.
Carbon monoxide is a(n) (a) and odorless gas.
Name six parts of an oil burner nozzle.
The steps to aggressively controlling the contamination of indoor air would involve ____.
locating and eliminating the source of contamination
providing adequate ventilation
providing methods for cleaning the air
All of the above.
A house is built on property whose soil is rich in uranium. The occupants of the house may ____.
be exposed to radon gas
be more susceptible to lung cancer
smell the pungent odor of the radon
Both a and b.
Electronic air cleaners generally have ____.
ionizing sections
charcoal filters
prefilters
All of the above.
A pleated filter ____.
does not clog up as quickly as a standard filter
has much more surface area than non-pleated filters
costs less than a standard filter
Both a and b.
One of the most common substances used as an absorber is ____.
charcoal
silica gel
fiberglass
foam rubber
Humidification generally relates to the process of causing water to ____ into the air.
a. condense
b. evaporate
c. be ionized
d. be filtered
The controller for a humidifier, a humidistat, has an element that is ____-sensitive.
moisture
light
infrared
temperature
Atomizing humidifiers discharge ____ into the air.
CO2
electronic ions
carbon dioxide
tiny water droplets
What level of mold contamination corresponds to areas from 10 to 30 square feet?
Level I.
Level II.
Level III.
Level IV.
What are the relative humidity limits recommended for residences?
20% to 40%.
30% to 50%.
40% to 60%.
50% to 70%.
A fiberglass media air filter contains a dust-holding adhesive that helps prevent particulates from ____.
migrating downstream
migrating upstream
absorbing odors
releasing spores
Because humidifiers use water, the evaporative surfaces and water reservoir must be cleaned and sanitized regularly to prevent the distributions of ____ by the moving airstream.
fungi
bacteria
algae
All of the above.
People who are active and spend a great deal of time outdoors are more likely to experience the effects of pollution.
True
False
Caution must be used with changing from one air-cleaning filter type to another. If a technician replaces a low-density filter with a high-density filter it is very likely that the airflow will be reduced.
True
False
The air in the home feels dry when it is heated because it expands, spreading out the moisture.
True
False
An atomizing humidifier should not operate when the furnace and blower are not operating.
True
False
The humidifier should exhaust directly onto air filters and electronic air cleaners.
True
False
____________ filters have large surface areas and require a deep filter case.
When odor is a concern, a filter containing (a) should be used.
In the ionizing section of an electronic air cleaner, the particles in the air are given a positive (a) .
HEPA filters can filter to a very high efficiency, down to a(n) (a) micrometers-sized particle or lower.
In electric furnace as well as heat pump systems, the recommended humidifier would be a(n) (a) type.
