Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the
question.
1)
1)
A method of measuring voltage across each component moving toward the malfunctioning load is
called:
A)
Hopscotching.
B)
Home chaining.
C)
Daisy running.
D)
Leap checking.
Answer:
A
A)
B)
C)
D)
2)
2)
Control voltage can be out because:
A)
Because of a blown 24 volt fuse.
B)
The part of the system that houses the transformer has no line voltage.
C)
Because of an issue with the transformer that supplies the control voltage.
D)
All of these could be the cause.
Answer:
D
A)
B)
C)
D)
3)
3)
Which of these methods used to determine which component in a circuit is not working properly?
A)
B)
C)
D)
Answer:
A
A)
B)
C)
D)
1
4)
4)
The resistance of ________ can accurately be predicted using Ohm’s law.
A)
relay solenoids
B)
resistors
C)
motors
D)
none of the above
E)
all of the above
Answer:
B
A)
B)
C)
D)
E)
5)
5)
If the circuit to the relay coil is not energizing the coil, the technician should:
A)
Check resistance in the circuit.
B)
Perform random voltage and ohm tests.
C)
Use the hopscotching technique to find the fault in the circuit.
D)
None of the above.
Answer:
C
A)
B)
C)
D)
6)
6)
A high resistance problem can be detected by:
A)
Checking the voltage drop across switches.
B)
Checking the voltage at the load.
C)
By checking current flow.
D)
Both A and B.
E)
Both B and C.
Answer:
D
A)
B)
C)
D)
E)
2
7)
7)
After determining that a high pressure switch is open, the next step is to:
A)
Determine why there is a high pressure condition.
B)
Determine whether or not the pressure switch should be open.
C)
Check the system high side pressure.
D)
All of the above.
Answer:
D
A)
B)
C)
D)
8)
8)
When replacing fuses be sure to match which of these ratings?
A)
Class
B)
Voltage
C)
Instantaneous current
D)
Amperage
E)
All of these should be matched.
Answer:
E
A)
B)
C)
D)
E)
9)
9)
Most circuits put all the controls on:
A)
One side of a load.
B)
Line voltage side of the load.
C)
Both sides of a load.
D)
The 24 volt side of the load.
Answer:
A
A)
B)
C)
D)
10)
10)
The resistance of an AC magnetic device will have ________ resistance than Ohm’s law predicts.
A)
a much lower
B)
a much higher
C)
the same
Answer:
A
A)
B)
C)
3
11)
11)
The ________ is used to identify all the controls in series with the load.
A)
component diagram
B)
electrical schematic
C)
pictorial diagram
D)
all of the above
Answer:
B
A)
B)
C)
D)
12)
12)
When hopscotch troubleshooting, follow the schematic and move the meter lead on the control
side of the circuit from one control to the next, checking the voltage in and out of the control. The
voltage will be ________ immediately after the control that is opening the circuit.
A)
B)
C)
D)
Answer:
C
A)
B)
C)
D)
13)
13)
When there is high resistance across the contacts when they are closed:
A)
Zero voltage will be read across the contacts.
B)
A voltage drop will be read across the contacts.
C)
Line voltage will be read across the contacts.
D)
None of the above.
E)
All of the above.
Answer:
B
A)
B)
C)
D)
E)
14)
14)
Any time a fuse is replaced or a breaker is reset, which of the following should be checked before
operating the system?
A)
Check the main power wire connections.
B)
Check all major line voltage loads for shorts or grounds.
C)
Run the system and check the amp draw on the circuit to the unit and at each major load.
D)
All of these should be checked.
Answer:
D
A)
B)
C)
D)
4
15)
15)
When troubleshooting split air conditioning systems be sure to check voltage to:
A)
The indoor unit only.
B)
The outdoor unit only.
C)
Both the indoor and outdoor units.
Answer:
C
A)
B)
C)
16)
16)
Hopscotching is an electrical troubleshooting technique that works by:
A)
Moving one meter lead from a point where voltage does not exists at a non– functioning
load point by point to where voltage is found.
B)
Moving both meter leads randomly recording points where voltage exists and does not
exist.
C)
Starting at a point where voltage exists and moving one lead at a time from point to point
toward the non–functioning load until voltage is lost.
D)
None of the above.
Answer:
C
A)
B)
C)
D)
17)
17)
Common air conditioning controls are switches that open or close based on a monitored condition
such as:
A)
Pressure.
B)
Current.
C)
Temperature.
D)
None of the above.
E)
All of the above.
Answer:
E
A)
B)
C)
D)
E)
5
18)
18)
The performance of an air–conditioning system can be determined by measuring the airflow and:
A)
The wet–bulb temperature difference across the evaporator coil.
B)
The dry–bulb temperature difference across the evaporator coil.
C)
The wet–bulb temperature difference across the condenser.
D)
The dry–bulb temperature difference across the condenser.
Answer:
A
A)
B)
C)
D)
19)
19)
Getting a chill when standing near a cold wall is an example of cooling by:
A)
B)
C)
D)
Answer:
C
A)
B)
C)
D)
20)
20)
The quantity of air a blower is moving is measured in:
A)
Capacity per minute – CFM.
B)
Force per minute – FPM.
C)
Cubic feet per minute – CFM.
D)
Feet per minute – FPM.
Answer:
C
A)
B)
C)
D)
21)
21)
Physically active people feel more comfortable at:
A)
Higher humidity.
B)
Higher temperatures and higher humidity.
C)
Lower temperatures.
D)
Higher temperatures.
Answer:
C
A)
B)
C)
D)
6
22)
22)
A process that moves horizontally from left to right across a psychrometric chart is:
A)
A sensible process.
B)
Changing the specific humidity of the air.
C)
A latent process.
D)
Not affecting the relative humidity of the air.
Answer:
A
A)
B)
C)
D)
23)
23)
A graphical representation of air properties is:
A)
An enthalpy chart.
B)
A temperature–pressure chart.
C)
A psychrometric chart.
D)
A pressure–temperature chart.
Answer:
C
A)
B)
C)
D)
24)
24)
Sweating when we work is an example of cooling by:
A)
B)
C)
D)
Answer:
D
A)
B)
C)
D)
25)
25)
Why does the air’s relative humidity affect comfort?
A)
Water molecules in the air act as thermal conductors.
B)
Human comfort is not affected by the relative humidity.
C)
Water molecules in the air act as thermal insulators.
D)
The relative humidity affects how rapidly perspiration can evaporate.
Answer:
D
A)
B)
C)
D)
7
26)
26)
What three environmental conditions have the most effect on comfort?
A)
Temperature, humidity, and air movement
B)
Temperature, humidity, and barometric pressure
C)
Altitude, barometric pressure, and humidity
D)
Temperature, altitude, and barometric pressure
Answer:
A
A)
B)
C)
D)
27)
27)
What is specific humidity?
A)
The amount of water in the air compared to the amount of water the air could hold
B)
The humidity level required for a particular application
C)
The relative humidity for any particular air sample
D)
The weight of water in each pound of dry air, measured in grains
Answer:
D
A)
B)
C)
D)
28)
28)
People maintain their steady internal body temperature by:
A)
Producing exactly the amount of heat needed to maintain body temperature.
B)
Sunning ourselves on radiant surfaces.
C)
Producing more internal heat than needed and expelling the extra heat.
D)
Adjusting our internal temperature to the surrounding conditions.
Answer:
C
A)
B)
C)
D)
29)
29)
The enthalpy lines are nearly parallel to the lines for:
A)
Grains of moisture.
B)
Wet–bulb temperature.
C)
Volume.
D)
Dry–bulb temperature.
Answer:
B
A)
B)
C)
D)
8
30)
30)
Relative humidity is measured using:
A)
A particle counter to count the grains of moisture in an air sample.
B)
Wet–bulb and dry–bulb temperature readings.
C)
Comparative volume measurements.
D)
Temperature and barometric pressure readings.
Answer:
B
A)
B)
C)
D)
31)
31)
What is a wet–bulb temperature reading?
A)
A temperature reading taken by placing the thermometer bulb in a stream of flowing liquid
B)
A temperature reading taken by submersing the thermometer bulb in a liquid
C)
A temperature measured after dipping the thermometer bulb in water
D)
A temperature measured with a water–soaked wick around the thermometer bulb
Answer:
D
A)
B)
C)
D)
32)
32)
What air property is measured in grains?
A)
Wet–bulb temperatures.
B)
The weight of air.
C)
Grains are used to measure the amount of water in the air.
D)
Relative humidity.
Answer:
C
A)
B)
C)
D)
33)
33)
The speed of air is measured in:
A)
Force per minute – FPM.
B)
Cubic feet per minute – CFM.
C)
Capacity per minute – CFM.
D)
Feet per minute – FPM.
Answer:
D
A)
B)
C)
D)
9
34)
34)
What is the industry standard rate of through–the–evaporator airflow in CFM per ton for most
air–conditioning equipment?
A)
400 CFM per ton
B)
1,200 CFM per ton
C)
800 CFM per ton
D)
2,000 CFM per ton
Answer:
A
A)
B)
C)
D)
35)
35)
The body cooling mechanisms include:
A)
Sublimation, hydration, and evaporation.
B)
Conduction, convection, radiation, and evaporation.
C)
Conduction, convection, radiation, and translation.
D)
Translation, transition, radiation, and evaporation.
Answer:
B
A)
B)
C)
D)
36)
36)
Static pressure readings are taken on a duct system by:
A)
Pointing the pressure–sensing tube into the airstream.
B)
Pointing the pressure–sensing tube perpendicular to the air stream.
C)
Subtracting the total pressure from the velocity pressure.
D)
Subtracting the velocity pressure from the total pressure.
Answer:
B
A)
B)
C)
D)
37)
37)
What is the CFM of air moving through an 8 in ×
10 induct if the air velocity is 800 FPM?
A)
8 × 10 = 80 sq in, 80/144 = 0.56 sq ft, 800 × 0.56 = 444 CFM
B)
8 × 10 = 80 sq in, 800/80 = 10 CFM
C)
800 CFM
D)
8 × 10 = 80 sq in, 80/144 = 0.56 sq ft, 800/0.56 = 1,428 CFM
Answer:
A
A)
B)
C)
D)
10
38)
38)
How is the air volume affected by temperature?
A)
Dry air increases in volume with an increase in temperature, humid air does not.
B)
Air volume is not affected by the temperature of the air.
C)
Air volume increases as the air temperature increases.
D)
Air volume decreases as the air temperature increases.
Answer:
C
A)
B)
C)
D)
39)
39)
If a technician wanted to accurately measure static pressure in a duct system, how would she
place the sensing probe of the magnehelic gauge?
A)
Perpendicular to airflow
B)
At the supply register outlet
C)
At the return grill inlet
D)
In line with the air flow
Answer:
A
A)
B)
C)
D)
40)
40)
A process that moves vertically up a psychrometric chart:
A)
Does not affect the specific humidity of the air.
B)
Does not affect the relative humidity of the air.
C)
Is a sensible process.
D)
Is a latent process.
Answer:
D
A)
B)
C)
D)
41)
41)
Total pressure readings are taken on a duct system by:
A)
Subtracting the velocity pressure reading from the static pressure reading.
B)
Pointing the pressure–sensing tube into the airstream.
C)
Adding the static pressure reading and the total pressure reading.
D)
Pointing the pressure–sensing tube perpendicular to the air stream.
Answer:
B
A)
B)
C)
D)
11
42)
42)
What gauges are used for measuring duct pressure?
A)
High–pressure gauges
B)
Compound gauges
C)
Magnehelic gauges
D)
Vacuum gauges
Answer:
C
A)
B)
C)
D)
43)
43)
In the cooling season, the comfort level can be improved at higher temperatures:
A)
By increasing air velocity.
B)
By removing humidity from the air.
C)
By removing humidity and increasing air velocity.
D)
By adding humidity to the air.
Answer:
C
A)
B)
C)
D)
44)
44)
Velocity pressure readings are taken on a duct system by:
A)
Pointing the pressure–sensing tube perpendicular to the air stream.
B)
Subtracting the static pressure from the total pressure.
C)
Pointing the pressure–sensing tube into the airstream.
D)
Subtracting the total pressure from the static pressure.
Answer:
B
A)
B)
C)
D)
45)
45)
How does the human body expel heat if all the surrounding environment is above the body
temperature?
A)
B)
C)
D)
Answer:
D
A)
B)
C)
D)
12
46)
46)
What is a HEPA filter?
A)
A filter that is at least 85 percent efficient at removing all sizes of particles
B)
A filter that is at least 95 percent efficient at removing all sizes of particles
C)
A filter that is at least 75 percent efficient at removing 1 micron particles
D)
A filter that is at least 99.97 percent efficient at removing 0.3 micron particles
Answer:
D
A)
B)
C)
D)
47)
47)
Air filters that work by passing the air and contaminants through a media and trapping the
contaminants in the media fibers use:
A)
Electronic precipitation.
B)
Mechanical filtration.
C)
Magnetic resonance particle removal.
D)
Velocity reduction particle precipitation.
Answer:
B
A)
B)
C)
D)
48)
48)
How often should a low–efficiency panel filter be changed?
A)
Monthly
B)
Once or twice a year
C)
Weekly
D)
Quarterly
Answer:
A
A)
B)
C)
D)
49)
49)
When homeowners neglect to change filters, airflow is reduced to the point where the cooling coil
can freeze. This can cause what critical component to fail prematurely?
A)
Condenser fan
B)
Blower fan
C)
Metering device
D)
Compressor
Answer:
D
A)
B)
C)
D)
13
50)
50)
What is the common operating voltage range on the cells of electronic air cleaners?
A)
6,000 to 10,000 volts DC
B)
480 to 600 volts DC
C)
25,000 to 50,000 volts DC
D)
120 to 240 volts AC
Answer:
A
A)
B)
C)
D)
51)
51)
An air contaminant that is most difficult to remove through common filtration methods is:
A)
B)
C)
D)
Answer:
A
A)
B)
C)
D)
52)
52)
While very effective at removing small contaminants, HEPA filters are not used in residential
applications because of what reason?
A)
They cause a high pressure drop in the duct.
B)
Not available in home centers
C)
Extremely high cost
D)
Low efficiency
Answer:
A
A)
B)
C)
D)
53)
53)
What maintenance does an electronic air cleaner require?
A)
Very little maintenance is required because the plates burn up the contaminants.
B)
Periodically cleaning the ionized plates
C)
Periodically replacing the ionized plates
D)
Annual replacement of the electrostatic precipitation unit
Answer:
B
A)
B)
C)
D)
14
54)
54)
MERV filter rating system:
A)
Compares the airflow resistance of different filters when they are new.
B)
Compares the airflow resistance of different filters when fully loaded.
C)
Compares the arrestance value of 12 different ranges of particle size.
D)
Compares the overall arrestance value of all sizes of particles.
Answer:
C
A)
B)
C)
D)
55)
55)
What is the advantage of the extended media surface area in pleated filters?
A)
Creates cyclonic filtration action between the pleats
B)
Allows the filter to be folded
C)
Much higher dust–holding ability
D)
Allows the filter to be flipped over when one side is dirty
Answer:
C
A)
B)
C)
D)
56)
56)
Air contaminants that can be removed by typical throwaway panel filters include:
A)
Talcum powder.
B)
Bacteria.
C)
Tobacco smoke.
D)
Pollen.
Answer:
D
A)
B)
C)
D)
57)
57)
How often should a renewable media, pleated surface be changed?
A)
Monthly
B)
Quarterly
C)
Once or twice a year
D)
Weekly
Answer:
C
A)
B)
C)
D)
15
58)
58)
One disadvantage of the highest MERV rated filters is that:
A)
High MERV filters require at least a 240 V power supply.
B)
The pressure drop across high MERV filters is more.
C)
The pressure drop across high MERV filters is less.
D)
High MERV filters do not clean the air as well as low MERV filters do.
Answer:
B
A)
B)
C)
D)
59)
59)
Utilizing a filter at decreased airflow levels will ________ the efficiency and ________ the pressure
drop in the duct.
A)
increase, decrease
B)
decrease, decrease
C)
decrease, increase
D)
not change, decrease
Answer:
A
A)
B)
C)
D)
60)
60)
What is the normal maximum air velocity across the face of a low–efficiency panel filter?
A)
1,000 feet per minute
B)
600 feet per minute
C)
300 feet per minute
D)
100 feet per minute
Answer:
C
A)
B)
C)
D)
61)
61)
________ light can be used inside a duct system to kill mold, fungus, bacteria, and other living
contaminants.
A)
B)
C)
D)
Answer:
D
A)
B)
C)
D)
16
62)
62)
What is the range of MERV ratings?
A)
From 1 to 20, with 1 representing the highest efficiency
B)
From 0% to 99%
C)
High, medium, and low efficiency
D)
From 1 to 20, with 20 representing the highest efficiency
Answer:
D
A)
B)
C)
D)
63)
63)
What factors should be considered when choosing an air filter?
A)
The desired efficiency at removing contaminants
B)
The airflow rating of the filter
C)
The smallest size particles it must filter out
D)
All of these factors should be considered
Answer:
D
A)
B)
C)
D)
64)
64)
Air cleaners that use high–voltage DC current to ionize particles in the air and attract them to
oppositely charged plates are a type of:
A)
Ultraviolet air sterilizer.
B)
Electrostatic air cleaner.
C)
Electro–mechanical particle arrester.
D)
Ionizing–plate air cleaner.
Answer:
D
A)
B)
C)
D)
65)
65)
Increasing the airflow across a filter:
A)
Decreases its efficiency.
B)
Has no effect on filter efficiency.
C)
Will reduce the air noise across the filter.
D)
Increases its efficiency.
Answer:
A
A)
B)
C)
D)
17
66)
66)
________ use DC voltage to attract dust and contaminants to an electrically charged media or
plate.
A)
HEPA filters
B)
Pleated filters
C)
Ultraviolet lights
D)
Electronic air cleaners
Answer:
D
A)
B)
C)
D)
67)
67)
Select the conditions that increase building pressure.
A)
Vented combustion appliances
B)
Infiltration
C)
Exhaust blowers
D)
Exfiltration
E)
Makeup air blowers
Answer:
E
A)
B)
C)
D)
E)
68)
68)
A desiccant wheel dehumidifier removes water from the air:
A)
By passing the air over a refrigerated evaporator coil.
B)
By spinning the air until water is removed by centrifugal force.
C)
By passing the air through an open gas flame.
D)
By absorbing it in a chemical desiccant.
Answer:
D
A)
B)
C)
D)
69)
69)
Heat recovery ventilators are recommended over energy recovery ventilators in cold climates:
A)
Because colder climates are not affected by humidity differences.
B)
Because there is so little heat in cold climates to exchange.
C)
To avoid freezing the water they remove.
D)
Because of the denser air.
Answer:
C
A)
B)
C)
D)
18
70)
70)
You are computing proper ventilation for a house with 1,500 sq ft of floor space, 8–ft ceilings, and
you wish to have 1 air change per hour. What is the total ventilation in CFM required?
A)
B)
C)
D)
Answer:
C
A)
B)
C)
D)
71)
71)
To calculate the CFM required to provide a given number of air changes in a building, you need:
A)
The floor area and ceiling height.
B)
The floor area, ceiling height, and an enthalpy chart.
C)
Floor area, ceiling height, and fan horsepower.
D)
A psychrometric chart and an enthalpy chart.
Answer:
A
A)
B)
C)
D)
72)
72)
Ventilation systems can be grouped by their effect on building pressure as:
A)
Contributing, offsetting, or correcting.
B)
Exhaust, supply, or balanced.
C)
Natural draft or forced draft.
D)
Small, medium, or large.
Answer:
B
A)
B)
C)
D)
73)
73)
Select the conditions that reduce building pressure. You may choose more than one.
A)
Make–up air blowers
B)
Infiltration
C)
Exhaust blowers
D)
Exfiltration
E)
Vented combustion appliances
Answer:
C, D, E
A)
B)
C)
D)
E)
19
74)
74)
A heat recovery ventilation system saves energy by:
A)
Decreasing the size of the indoor air–conditioning system blower.
B)
Preheating the ventilation supply air with electric heat strips.
C)
Exchanging heat between the supply and exhaust air streams.
D)
Preheating the ventilation exhaust air with electric heat strips.
Answer:
C
A)
B)
C)
D)
75)
75)
Dehumidification makes us feel cooler by:
A)
Speeding up the process of evaporation on our skin.
B)
Actually reducing the air temperature through evaporation in the dehumidifier.
C)
Slowing down the process of evaporation on our skin.
D)
Improving the efficiency of air–cooled condensers.
Answer:
A
A)
B)
C)
D)
76)
76)
If a modern home is built too tightly, the air change rate per hour is reduced. What should be done
to increase ventilation to safe levels?
A)
Reduce the insulation in the home.
B)
Increase the blower fan speed.
C)
Use a mechanical ventilation system to bring in fresh air.
D)
Open the ground floor windows.
Answer:
C
A)
B)
C)
D)
77)
77)
What type of system normally uses desiccant wheel dehumidifiers?
A)
Whole house residential dehumidifier
B)
Small console unit
C)
Large industrial or commercial system
D)
Walk–in freezer
Answer:
C
A)
B)
C)
D)
20