Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the
question.
1)
1)
What type of thermostat is typically used with electric baseboard heaters?
A)
Low–voltage thermostats
B)
Line–voltage thermostats
C)
Wireless thermostats
D)
Thermostats are not used with baseboard heaters.
Answer:
B
A)
B)
C)
D)
2)
2)
What is the advantage of a fusible link?
A)
The melting temperature of the alloy remains constant over time.
B)
The melting temperature of the alloy changes with the air.
C)
The melting temperature of the alloy remains inconsistent over time.
D)
The melting temperature of the alloy does not remain constant.
Answer:
A
A)
B)
C)
D)
3)
3)
What is the kilowatt rating of an electric furnace rated at 240 V and 30 A?
A)
Kilowatts cannot be calculated using only volts and amps.
B)
240 V/30 A = 8 kW
C)
240 V × 30 A = 7,200 W, which is 72 kW
D)
240 V × 30 A = 7,200 W, which is 7.2 kW
Answer:
D
A)
B)
C)
D)
1
4)
4)
When electric strip heat is used with a heat pump, when is the electric strip heat energized?
A)
The electric strip heat comes on in the first stage, and the heat pump in the second stage.
B)
The heat pump comes on in the first stage, and the strips in the second stage.
C)
Both the heat pump and the strips come on in the second stage.
D)
Both the heat pump and strips come on in the first stage.
Answer:
B
A)
B)
C)
D)
5)
5)
How can a multistage thermostat be applied to control an electric furnace?
A)
The strips will receive 120 volts in the first stage and 240 volts in the second stage.
B)
The strips will come on in the first stage and the fan in the second stage.
C)
The blower will come on in the first stage and the strips in the second stage.
D)
Fifty percent of the strips will be energized in the first stage and the rest in the second stage.
Answer:
D
A)
B)
C)
D)
6)
6)
What power source does a heater normally operate on?
A)
B)
C)
D)
Answer:
D
A)
B)
C)
D)
7)
7)
As a safety precaution, electric duct heaters should be wired so that they will not operate unless:
A)
The second stage of the thermostat is closed.
B)
Other forms of heat are not operating.
C)
The fan is operating.
D)
Extra heat is needed.
Answer:
C
A)
B)
C)
D)
2
8)
8)
When does the blower on an electric furnace operate?
A)
The blower operates whenever the last heating element is energized.
B)
The blower operates whenever any of the heating elements are energized.
C)
The blower operates independently of the heating elements.
D)
The blower operates when the first heating element is energized.
Answer:
B
A)
B)
C)
D)
9)
9)
What controls the heating elements in most electric furnaces?
A)
B)
C)
D)
Answer:
B
A)
B)
C)
D)
10)
10)
What happens when the outdoor temperature drops?
A)
The heat pump will adapt the inside temperature anytime the outdoor temperature drops.
B)
The heat pump will be able to maintain a comfortable indoor temperature.
C)
The heat pump will automatically turn on when the outdoor temperature drops.
D)
The heat pump alone may not be able to maintain a comfortable indoor temperature.
Answer:
D
A)
B)
C)
D)
11)
11)
If electric heating elements are used in conjunction with a heat pump, when do they operate?
A)
The electric heating elements operate simultaneously with the heat pump.
B)
The electric heating elements operate in the first stage.
C)
The electric heating elements operate whenever the heat pump is not operating.
D)
The electric heating elements operate in the second stage.
Answer:
D
A)
B)
C)
D)
3
12)
12)
What material are electric heater coils often made from?
A)
Copper and brass
B)
Silicon carbide
C)
Nickel–chrome alloy wire
D)
Steel and chrome alloy wire
Answer:
C
A)
B)
C)
D)
13)
13)
What is one common application of an electric heating furnace?
A)
Combining it with a multisystem heat pump
B)
Combining it with a triple–system heat pump
C)
Combining it with a split–system heat pump
D)
Combining it with a cool heat pump
Answer:
C
A)
B)
C)
D)
14)
14)
How warm is the supply air of an electric furnace compared to gas– or oil–fired furnaces?
A)
Supply air temperatures for electric furnaces are higher.
B)
Supply air temperatures for electric furnaces are lower than those for oil furnaces, but
higher than those for gas furnaces.
C)
Supply air temperatures for electric furnaces are lower.
D)
Supply air temperatures are about the same.
Answer:
C
A)
B)
C)
D)
15)
15)
Inline cartridge fuses are used:
A)
To protect individual heating elements, groups of heating elements, or entire furnaces.
B)
To protect individual heating plates, groups of heating fans, or half of the furnace.
C)
To protect individual heating elements, groups of heating furnaces, or entire furnaces.
D)
To protect individual heating plates, groups of heating elements, or entire furnaces.
Answer:
A
A)
B)
C)
D)
4
16)
16)
What is the formula to figure out how much electric heat is produced by an electric furnace?
A)
Volts = Watts × Amps
B)
Watts = Volts ×
Gas
C)
Amps = Amps × Volts
D)
Watts = Volts ×
Amps
Answer:
D
A)
B)
C)
D)
17)
17)
What is the heat output of an electric furnace rated at 15 kilowatts on 240 volts?
A)
15 kW ×
3,412 = 51,180 BTU/hr
B)
15 kW ×
240 = 36,000 BTU/hr
C)
15 kW ×
1,000 = 15,000 BTU/h
D)
The heat output cannot be calculated using the kilowatt output.
Answer:
A
A)
B)
C)
D)
18)
18)
An advantage of a warm–air electric furnace compared to an oil or gas furnace is:
A)
Lower power requirements.
B)
No vent pipes, chimney, or makeup air are required.
C)
Warmer supply air temperatures.
D)
Lower operating cost in most parts of the country.
Answer:
B
A)
B)
C)
D)
19)
19)
What is one important thing you must do when replacing a heating element rack?
A)
Ensure that you specify the model and serial number of the furnace where the rack will go.
B)
Ensure that you specify the serial number of the nickel–chrome alloy.
C)
Ensure that you specify the model number of the heating element.
D)
Ensure that you specify the serial number of the heating element.
Answer:
A
A)
B)
C)
D)
5
20)
20)
Baseboard heaters are ideally suited for where?
A)
B)
C)
D)
Answer:
B
A)
B)
C)
D)
21)
21)
How are electric heating elements rated?
A)
Electric heating elements are rated in joules.
B)
Electric heating elements are rated in degrees Fahrenheit.
C)
Electric heating elements are rated by their kW capacity.
D)
Indoor or outdoor applications.
Answer:
C
A)
B)
C)
D)
22)
22)
What protective devices do electric furnaces typically have?
A)
Magnetic overload relays
B)
Pilot duty thermal overload relays
C)
Phase loss monitors
D)
Fusible links and thermal overloads in series with the heating elements
Answer:
D
A)
B)
C)
D)
23)
23)
Which location is the best for installing electric baseboard heaters?
A)
Up high, near the ceiling
B)
Along the walls of an inside hallway
C)
Along an outside wall
D)
On an inside wall
Answer:
C
A)
B)
C)
D)
6
24)
24)
Each electric furnace is designed to hold which of the following?
A)
A specific type and size of heating fan
B)
A specific type and size of heating oxidation
C)
A specific type and size of heating element rack
D)
A specific type and size of the nickel–chrome alloy
Answer:
C
A)
B)
C)
D)
25)
25)
The disconnect switch for the unit:
A)
Should be located within sight of the furnace.
B)
Can be the breaker in the power distribution panel feeding the furnace circuit.
C)
Should be located in an easily accessible location, like a utility closet or garage.
D)
Should be attached to the furnace cabinet.
Answer:
A
A)
B)
C)
D)
26)
26)
When installing electric furnaces, all aspects of the power wiring circuit are crucial because of:
A)
The high current draw of electric furnaces.
B)
The sensitivity of the delicate electronic controls used to control electric heating elements.
C)
The higher voltage that is supplied to electric furnaces.
D)
The intolerance of electric heating elements to voltage variation.
Answer:
A
A)
B)
C)
D)
27)
27)
When checking an electric furnace, the technician should check:
A)
The voltage and current draw of each strip.
B)
The temperature of the outside of the furnace cabinet.
C)
The frequency of the supply voltage.
D)
The loops per inch of each strip heater.
Answer:
A
A)
B)
C)
D)
7
28)
28)
How is voltage drop through the power wire to the unit checked?
A)
The difference between the minimum and maximum allowable nameplate voltages is the
voltage drop.
B)
The difference in voltage before and after starting the furnace is the voltage drop.
C)
Measure the resistance of the power wire from the source to the furnace and multiply it
times the furnace operating current.
D)
The difference between the nameplate voltage and the actual operating voltage is the
voltage drop.
Answer:
B
A)
B)
C)
D)
29)
29)
What will be the capacity of an electric furnace rated at 15 kW on 240 V if it is operated at 208 V?
A)
The capacity will be increased to 20 kW.
B)
The capacity will remain the same, 15 kW.
C)
The capacity will be reduced to 11 kW.
D)
The capacity will be reduced by exactly 32 W.
Answer:
C
A)
B)
C)
D)
30)
30)
What is the minimum current rating for the disconnect switch of a unit with a minimum circuit
ampacity rating of 45 A?
A)
45 A
B)
45 A × 1.15 = 51.75 A
C)
45 A × 1.5 = 67.5 A
D)
45 A × 1.25 = 56.25 A
Answer:
B
A)
B)
C)
D)
31)
31)
The most important part of an electric furnace installation is:
A)
The installation of the pump.
B)
The sizing of the wiring.
C)
The placement of the thermostat.
D)
The size of the fan.
Answer:
B
A)
B)
C)
D)
8
32)
32)
The house electrical service should be checked before installing a unit in an older house because
the electrical service in many older houses:
A)
Operates on DC current, and electric furnaces require AC current.
B)
Uses a different style of circuit connector that is not compatible with electric furnaces.
C)
Will not supply the current requirements of an electric furnace.
D)
Will not supply 240 V to major loads.
Answer:
C
A)
B)
C)
D)
33)
33)
Which of the following unit clearances is typically the largest?
A)
A 6–inch clearance from all combustibles on all sides
B)
Service clearance
C)
Clearance for the vent
D)
A 12–inch clearance from all items that can be damaged by the strong magnetic force field
generated by the furnace
Answer:
B
A)
B)
C)
D)
34)
34)
Which of the following methods should NOT be used to support an electric furnace?
A)
Suspending it from floor joists
B)
Sitting it upright on the return air box
C)
Resting it on the ceiling joists
D)
Suspending it from roof rafters
Answer:
C
A)
B)
C)
D)
35)
35)
Which of the following is a good suggestion when bending the furnace plenum flange to
minimize distortion?
A)
Make a series of larger angled bends along the length of the flange.
B)
Make a series of rips along the length of the flange.
C)
Make a series of smaller angled bends along the length of the flange.
D)
Make a series of smaller angled bends along the width of the flange.
Answer:
C
A)
B)
C)
D)
9
36)
36)
After installing a new electric furnace, the technician measures the temperature rise and finds that
it exceeds the manufacturer’s specifications. To reduce the temperature rise, the technician should:
A)
Decrease the fan speed.
B)
Unwire one of the strip heaters.
C)
Reduce the incoming voltage to the furnace.
D)
Increase the fan speed.
Answer:
D
A)
B)
C)
D)
37)
37)
The overcurrent protection for an electric furnace should be:
A)
At least as large as the maximum overcurrent protection listed on the unit data plate.
B)
No larger than the maximum overcurrent protection listed on the unit data plate.
C)
No larger than the minimum circuit ampacity rating used to size the wire.
D)
The same size as the minimum circuit ampacity rating for the wire.
Answer:
B
A)
B)
C)
D)
38)
38)
What happens when a furnace is installed on lower–voltage supplies?
A)
The furnace will not operate correctly if it is installed on lower–voltage supplies.
B)
There is a significant loss of heating capacity.
C)
There is a significant gain in heating capacity.
D)
Nothing happens when furnaces are installed on lower–voltage supplies.
Answer:
B
A)
B)
C)
D)
39)
39)
How can a furnace problem be located?
A)
By measuring the voltage of the power–handling components
B)
By measuring the furnace plates using the thermostat
C)
By measuring the amount of cold air coming out of the vent
D)
By measuring the amount of heat coming out of the vent
Answer:
A
A)
B)
C)
D)
10
40)
40)
Why should electric furnaces NOT rest directly on the ceiling joists?
A)
Most electric furnaces should have a 6–inch clearance to combustibles on all sides.
B)
Most electric furnaces cannot be installed in the horizontal position.
C)
The ceiling will act as a sounding board and transmit the blower sound throughout the
house.
D)
Most electric furnaces are too heavy to be supported by ceiling joists.
Answer:
C
A)
B)
C)
D)
41)
41)
Which of the following items do aluminum conductors require an application of during
installation?
A)
Iron
B)
Antioxidation paste
C)
Nickel
D)
Oxidation paste
Answer:
B
A)
B)
C)
D)
42)
42)
Compared to the installation of a gas or oil furnace, an electric furnace installation is:
A)
More complex, but generally easier.
B)
Less complex and easier.
C)
Less complex, but generally more difficult.
D)
About the same complexity and difficulty.
Answer:
B
A)
B)
C)
D)
43)
43)
The power wire for an electric furnace should be:
A)
Sized to handle the minimum circuit ampacity on the data plate.
B)
12 AWG in most cases.
C)
The same wire gauge as the internal wiring in the furnace.
D)
No larger than 10 AWG in order to avoid voltage drop.
Answer:
A
A)
B)
C)
D)
11
44)
44)
If aluminum power wire is used, to make a safe connection the installer should make sure:
A)
That the furnace power connectors are rated for aluminum wire.
B)
To use an aluminum–tipped screwdriver to tighten the lugs.
C)
The aluminum wire is one size smaller than a comparable copper wire.
D)
To first spray the lugs with insulating spray.
Answer:
A
A)
B)
C)
D)
45)
45)
“The minimum distances from each of the furnace surfaces to any combustible materials”
describes which of the following?
A)
The furnace clearance minimums
B)
The furnace clearance maximums
C)
The furnace regulations
D)
The furnace measurements
Answer:
A
A)
B)
C)
D)
46)
46)
The terminal and wire resistance values are critical in electric furnaces because the large current
draw from the strip heaters:
A)
Increases if the overall circuit resistance increases.
B)
Causes arcing to ground at connections with a high resistance.
C)
Causes electro radiation.
D)
Turns even small resistances into heat that accelerates oxidation.
Answer:
D
A)
B)
C)
D)
47)
47)
Why is a visual check of the heating strips on an electric furnace difficult to accomplish?
A)
It is not safe to look at an operating strip heater without wearing protective radiant
reflecting headgear made specifically for safe viewing.
B)
The heaters cannot be seen without removing them from the furnace.
C)
Electric strip heaters are complex devices.
D)
It is difficult to spot a break in a strip heater because of the small size wire used.
Answer:
B
A)
B)
C)
D)
12
48)
48)
What could cause a false high reading for the supply–air temperature?
A)
The temperature is taken after the unit has been running for too long.
B)
The temperature is taken with the blower on at the same time the heating elements are on.
C)
The probe is inserted in the supply plenum in a direct line of sight with the heating
elements.
D)
The temperature is taken with a probe inserted upside down.
Answer:
C
A)
B)
C)
D)
49)
49)
The most effective method of checking the heating elements of an electric furnace during
operation is:
A)
Checking the amp draw of each heat strip.
B)
Checking the resistance of each heat strip.
C)
A visual inspection.
D)
Measuring the temperature of each heat strip.
Answer:
A
A)
B)
C)
D)
50)
50)
Overheating can cause a terminal to discolor or the wiring insulation to melt. What should you
consider when repairing the wire or the terminal?
A)
It is recommended to replace the entire wire with another wire of the same or larger gauge.
If the terminal is on a relay, sequencer, or fuse block, the component should also be replaced
in addition to the wire.
B)
Replace the terminal end only. It is okay to cut off the end and repair the wire. If the
terminal is on a relay, sequencer, or fuse block, the component should also be replaced in
addition to the wire.
C)
It is recommended to replace the entire wire with another wire of the same or larger gauge.
If the terminal is on a relay, sequencer, or fuse block, only the wire needs to be replaced. The
component does not need to be replaced.
D)
Replace the terminal end only. It is okay to cut off the end and repair the wire. If the
terminal is on a relay, sequencer, or fuse block, only the wire needs to be replaced. The
component does not need to be replaced.
Answer:
A
A)
B)
C)
D)
13
51)
51)
What would happen if metal debris fell into the heating element?
A)
It is not possible for debris to fall into a heating element.
B)
The debris could cause the heating element to fail and never turn on.
C)
The debris would do nothing.
D)
The debris could cause the heating element to turn on.
Answer:
D
A)
B)
C)
D)
52)
52)
A technician takes the following readings while checking the operation of an electric furnace with
two heat strips: 220 V, 36 A, 70°F return air temperature, and 120°F supply air temperature. What
is the airflow through the furnace?
A)
220 × 36 ×
3.41
(120 – 70) ×
1.08 = 27,002
50 = 500 CFM
B)
220 × 36 ×
3.41
(120 – 70) = 27,002
50 = 540 CFM
C)
(120 — 70) ×
1.08 ×
10 = 540 CFM
D)
220 × 36
(120 – 70) = 27,002
50 = 158 CFM
Answer:
A
A)
B)
C)
D)
53)
53)
Whenever a thermal limit or fusible link needs replacing, the technician should always check:
A)
The air filter and airflow.
B)
The transformer control voltage.
C)
The power wire for voltage drop.
D)
The thermostat calibration.
Answer:
A
A)
B)
C)
D)
54)
54)
When replacing a transformer, the technician should always check:
A)
The temperature rise across the furnace.
B)
The 24 V control circuit for shorts.
C)
The air filter and airflow.
D)
The continuity of the electric strip heaters.
Answer:
B
A)
B)
C)
D)
14
55)
55)
A technician finds that a wire in an electric furnace is brittle and discolored from overheating. The
technician should:
A)
Cut off the overheated end and splice on a short length of similar wire using high–quality
electrical tape.
B)
Replace the entire wire.
C)
Cut off the overheated end and add a short length of similar wire using a wire nut.
D)
Cut off the overheated end, strip the remaining wire end, and reinstall it.
Answer:
B
A)
B)
C)
D)
56)
56)
Why is it important to cycle the furnace on and off several times when replacing a sequencer?
A)
To make sure the power is working correctly.
B)
To make sure that only the heating elements are coming on and not the blower.
C)
To make sure the heating elements and the blower are turning on at the same time.
D)
To make sure the heating elements and the blower are switching on and off in the correct
cycle.
Answer:
D
A)
B)
C)
D)
57)
57)
What is the purpose of a Tattle Tale?
A)
To tell the technician if the furnace is turning on properly
B)
To tell the electric furnace to turn off if the limits have been exceeded
C)
To prevent the limits from ever being exceeded in the furnace
D)
To tell the technician if the limits have opened at any time during the unit’s operation
Answer:
D
A)
B)
C)
D)
58)
58)
An electric furnace that runs continuously, regardless of the thermostat setting, probably has:
A)
A bad transformer.
B)
An open fusible link.
C)
A stuck sequencer.
D)
An open strip heater.
Answer:
C
A)
B)
C)
D)
15
59)
59)
An electric furnace that does not operate, regardless of the thermostat setting, may have:
A)
An open fusible link.
B)
A dirty air filter.
C)
A bad sequencer coil.
D)
An open strip heater.
Answer:
C
A)
B)
C)
D)
60)
60)
To determine if the contacts inside a sequencer are faulty, the technician should energize the relay
and use an ohmmeter set to the RX1 scale. Which of these resistance readings indicates that the
sequencer must be replaced?
A)
Between 0 and 0.1
B)
Greater than 0.1
C)
Less than 0.1
D)
0
Answer:
B
A)
B)
C)
D)
61)
61)
What is the purpose of the white ceramic pieces on the strip heaters?
A)
They make it easier to identify where the heat strips are installed.
B)
They concentrate the heat of the strips.
C)
They seal the heat produced by the strips inside the furnace.
D)
They insulate the heater wire from the metal frame supporting it.
Answer:
D
A)
B)
C)
D)
16
62)
62)
Given the following readings from an electric furnace, use the formula to calculate airflow.
CFM =V ×
A × 3.412
T × 1.08
What is the airflow in CFM?
Voltage at strips 240 V
Amp draw of strips 22.6 A
Return–air temperature 65°F
Supply–air temperature 120°F
A)
The airflow is 336 CFM.
B)
The airflow is 312 CFM.
C)
The airflow is 264 CFM.
D)
The airflow is 363 CFM.
Answer:
B
A)
B)
C)
D)
63)
63)
The resistance reading of an open heating element is:
A)
Infinite ohms, which would show OL on most digital meters.
B)
It is not possible to check the resistance of an open heating element.
C)
A measurable resistance of approximately 12.
D)
0, which would show as 0.0 to 0.1 on most digital meters.
Answer:
A
A)
B)
C)
D)
64)
64)
An electric furnace operates, but produces less heat than it used to produce. Which of the
following could NOT be the cause?
A)
A bad transformer
B)
A bad sequencer coil
C)
An open fusible link
D)
An open strip heater
Answer:
A
A)
B)
C)
D)
17
65)
65)
The resistance reading of a good 5 kW heating element is:
A)
Infinite ohms, which would show OL on most digital meters.
B)
A measurable resistance of approximately 12.
C)
A measurable resistance of approximately 50,000.
D)
0, which would show 0.0 to 0.1 on most digital meters.
Answer:
B
A)
B)
C)
D)
66)
66)
The two general types of sequencers used on electric furnaces are:
A)
High–current sequencers and low–current sequencers.
B)
Mechanical and electronic.
C)
Fast–acting sequencers and slow–acting sequencers.
D)
Individual time–delay relays and all–in–one sequencers that control all the strips and the
blower motor.
Answer:
D
A)
B)
C)
D)
67)
67)
A visual inspection reveals a broken heating element, an open fusible link, and a cracked ceramic
insulator. Which of these parts must be replaced?
A)
Only the heating element needs to be replaced.
B)
All broken parts should be replaced.
C)
Only the heating element and the fusible link need to be replaced.
D)
Only the fusible links need to be replaced.
Answer:
B
A)
B)
C)
D)
18
68)
68)
If a voltmeter shows a reading of 240 V across the thermal limit to a strip heater on an electric
furnace, it indicates:
A)
The limit is close, completing the circuit to the heater.
B)
The limit is open, completing the circuit to the heater.
C)
The limit is closed, breaking the circuit to the heater.
D)
The limit is open, breaking the circuit to the heater.
Answer:
D
A)
B)
C)
D)
69)
69)
The furnace has one or more broken heating elements or one or more fusible links open. What
should the technician do?
A)
The technician should check the furnace airflow.
B)
The technician should check the power source to the furnace.
C)
The technician should replace all the heating elements.
D)
The technician should replace all the fusible links.
Answer:
A
A)
B)
C)
D)
70)
70)
What problems can be caused by overlubricating a blower motor?
A)
This could eventually cause the motor windings to short out.
B)
It is not possible to overlubricate a motor.
C)
The motor would run more effectively with the extra lubrication.
D)
The blower motor could run faster than specifications recommend.
Answer:
A
A)
B)
C)
D)
19
71)
71)
What makes the main valve in the reversing valve shift from one side to the other?
A)
Pressure difference from one side of the valve to the other
B)
A solenoid coil creates a magnetic field that pulls the valve to one end and repels it to the
other.
C)
An electronic stepper motor mounted on one end of the reversing valve
D)
A small gear motor that is operated on 24 V engages gears on the back of the valve core.
Answer:
A
A)
B)
C)
D)
72)
72)
How does the heating–cycle charge compensator differ during the heating and cooling cycles?
A)
The temperature of the coolant is lower during the cooling cycle.
B)
Less coolant needs to be circulated during the heating cycle.
C)
Most of the refrigerant leaves during the cooling cycle.
D)
Most of the refrigerant leaves during the heating cycle.
Answer:
C
A)
B)
C)
D)
73)
73)
How can an air–source heat pump heat when the outdoor temperature is cold?
A)
Air–source heat pumps only use the outdoor air in the cooling season.
B)
All heating is accomplished with electrical resistance heaters, so the air temperature is
irrelevant.
C)
All molecules contain some heat until they reach absolute zero (–460°F).
D)
The friction of the air passing over the outdoor coil raises the temperature.
Answer:
C
A)
B)
C)
D)
20