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153)
153)
The indoor fan on an oil furnace is controlled by:
A)
A temperature-sensing fan switch.
B)
The primary control.
C)
A centrifugal switch on the oil burner motor.
D)
Either a temperature-sensing fan switch or the primary control.
Answer:
D
Explanation:
A)
B)
C)
D)
154)
154)
What should be done if a furnace with a tripped primary control has oil is in the combustion
chamber?
A)
Clean out the oil before firing the furnace.
B)
Burn off the excess oil using a propane torch before firing the furnace.
C)
Push the reset button and let the fire burn off the excess oil.
D)
Disconnect the vent connector before firing the furnace to avoid soot accumulation in the
vent.
Answer:
A
Explanation:
A)
B)
C)
D)
155)
155)
What might be the problem if there are carbon deposits on the refractory?
A)
Cracked heat exchanger
B)
Defective nozzle
C)
Defective relay protector
D)
Improper heat anticipator setting
Answer:
B
Explanation:
A)
B)
C)
D)
156)
156)
What two manual resets do all oil burners have?
A)
The primary control reset and the secondary control reset
B)
The integrated furnace circuit breaker and the high fuel pressure reset
C)
The high limit manual reset and the smoke sensor manual reset
D)
The primary control reset and the oil burner motor overload manual reset
Answer:
D
Explanation:
A)
B)
C)
D)
41
157)
157)
Which type of space heater would be ideal for the spot removal of ice or snow on your doorsteps
or patio deck?
A)
Electric infrared space heaters
B)
Gas-infrared space heaters
C)
Convection baseboard electric space heaters
D)
Forced-air electric space heaters
Answer:
A
Explanation:
A)
B)
C)
D)
158)
158)
Which type of electrical space heater has the greatest potential for overheating?
A)
Convection baseboard electric space heaters
B)
Forced-air electric space heaters
C)
Cabinet-type electric space heaters
D)
Suspended-force fan-unit electric space heaters
Answer:
A
Explanation:
A)
B)
C)
D)
159)
159)
Why do many building codes restrict the use of unvented gas-fired space heaters?
A)
They heat unevenly.
B)
They tend to be less efficient than vented space heaters.
C)
It is difficult to connect ductwork to them.
D)
They release all their combustion products into the space they are heating.
Answer:
D
Explanation:
A)
B)
C)
D)
42
160)
160)
Which type of electric space heater is often used in office and home settings for uniform room
temperature control?
A)
Convection baseboard electric space heaters
B)
Forced-air electric space heaters
C)
Suspended-force fan-unit electric space heaters
D)
Cabinet-type electric space heaters
Answer:
B
Explanation:
A)
B)
C)
D)
161)
161)
Where is a "direct vent" space heater installed?
A)
Any place that still allows a vent pipe to run to the outside
B)
In an exterior wall
C)
Typically they are free-standing in the room being heated.
D)
In an interior wall
Answer:
B
Explanation:
A)
B)
C)
D)
162)
162)
Which type of space heater is generally the least expensive to purchase?
A)
Kerosene space heater
B)
Vented gas space heater
C)
Electric space heater
D)
Unvented gas space heater
Answer:
C
Explanation:
A)
B)
C)
D)
163)
163)
How does a kerosene heater prepare its fuel for combustion?
A)
Oil is vaporized by the heat of combustion and the hot surface of the combustion chamber.
B)
Kerosene does not need to be prepared for combustion because it is highly volatile.
C)
Oil is atomized using a high-pressure pump and an atomizing nozzle.
D)
Oil is atomized using a centrifugal motor that slings small droplets of oil into the
combustion chamber.
Answer:
A
Explanation:
A)
B)
C)
D)
43
164)
164)
How do infrared heaters transfer heat?
A)
They heat the air molecules, and the air heats the people in the room.
B)
They only heat objects that they are touching.
C)
They directly heat people and objects through radiation.
D)
Air is circulated over them and distributed via ductwork.
Answer:
C
Explanation:
A)
B)
C)
D)
165)
165)
Why do some gas furnaces NOT require an electrical power supply?
A)
The gas valve is operated with the voltage generated by the thermopile safety.
B)
They are ignited and extinguished manually with no thermostatic control.
C)
No gas furnaces require electricity; they operate on gas.
D)
Once lighted, they never shut off.
Answer:
A
Explanation:
A)
B)
C)
D)
166)
166)
Which type of space heater is generally the easiest to maintain?
A)
Electric space heater
B)
Kerosene space heater
C)
Vented gas space heater
D)
Unvented gas space heater
Answer:
A
Explanation:
A)
B)
C)
D)
167)
167)
Where are "salamanders" used?
A)
They are most often used in bedrooms to supplement central heating systems on unusually
cold nights.
B)
They are specifically designed to heat aquatic biospheres containing amphibians.
C)
They are often used during building construction to supply temporary heat.
D)
They are used to preheat the return air in air source heat pumps.
Answer:
C
Explanation:
A)
B)
C)
D)
44
168)
168)
The three types of gas space heaters are:
A)
Category I, category II, and category III.
B)
Vented, unvented, and catalytic.
C)
Low pressure, medium pressure, and high pressure.
D)
Natural gas, propane, and kerosene.
Answer:
B
Explanation:
A)
B)
C)
D)
169)
169)
As the outdoor temperature decreases, the maximum relative humidity that is safe to maintain
indoors:
A)
Stays the same, 50 percent.
B)
Increases.
C)
Stays the same, 60 percent.
D)
Decreases.
Answer:
D
Explanation:
A)
B)
C)
D)
170)
170)
Which type of humidifier uses the most water?
A)
Plate
B)
Rotating plate
C)
Rotating-drum
D)
Bypass
Answer:
D
Explanation:
A)
B)
C)
D)
171)
171)
How much moisture can air hold when it is heated to 70°F?
A)
110 grains per pound
B)
105 grains per pound
C)
50 grains per pound
D)
200 grains per pound
Answer:
A
Explanation:
A)
B)
C)
D)
45
172)
172)
One advantage of steam humidifiers is that:
A)
They use less energy than evaporative humidifiers.
B)
They do not have a water sump.
C)
They provide the energy required to evaporate the water.
D)
They operate on 24 V.
Answer:
C
Explanation:
A)
B)
C)
D)
173)
173)
The type of humidifier that uses a component submerged in water that circulates is the:
A)
Rotating plate.
B)
Plate.
C)
Bypass.
D)
Rotating-drum.
Answer:
D
Explanation:
A)
B)
C)
D)
174)
174)
The rotating plate is similar to which other type of humidifier?
A)
Rotating-drum
B)
Atomizing
C)
Steam
D)
Vaporizing
Answer:
A
Explanation:
A)
B)
C)
D)
175)
175)
Adding humidity to heated air:
A)
Decreases the perceived room temperature.
B)
Has no effect on perceived room temperature.
C)
Increases the perceived room temperature.
D)
Reduces the level of carbon particles generated by heat pumps.
Answer:
C
Explanation:
A)
B)
C)
D)
46
176)
176)
Which type has the highest capacity of any type of humidifier?
A)
Vaporizing
B)
Bypass
C)
Atomizing
D)
Evaporating
Answer:
A
Explanation:
A)
B)
C)
D)
177)
177)
Which of the following problems could occur if a humidifier is not regularly cleaned and checked
for operation?
A)
Mold growth
B)
CO poisoning
C)
Excessive dryness
D)
Nickel in the water supply
Answer:
A
Explanation:
A)
B)
C)
D)
178)
178)
Which of the following humidifiers are ideal to use with heat pumps, electric furnaces, and
high-efficiency furnaces?
A)
Atomizing
B)
Steam
C)
Bypass
D)
Evaporating
Answer:
B
Explanation:
A)
B)
C)
D)
179)
179)
What types of humidifiers work best with heat pump systems?
A)
Steam humidifiers
B)
Plate humidifiers
C)
Water spray misters
D)
Wetted element
Answer:
A
Explanation:
A)
B)
C)
D)
47
180)
180)
Why is it possible to use smaller vent pipes in higher-efficiency units?
A)
Condensation pushes the gas through the pipes.
B)
The temperature of the flue gases is higher.
C)
The volume of the flue gases is greater.
D)
Volume and temperature of flue gases are lower.
Answer:
D
Explanation:
A)
B)
C)
D)
181)
181)
Why must condensate pumps used with condensing furnaces be approved for furnace condensate
use?
A)
The condensate from a furnace is mildly acidic and can damage the materials in some
condensate pumps.
B)
The condensate from a furnace is mildly alkaline and can damage the materials in some
condensate pumps.
C)
The furnace manufacturer will void the warranty if the wrong condensate pump is used.
D)
The condensate from a furnace is flammable and only furnace-rated condensate pumps can
pump flammable liquid.
Answer:
A
Explanation:
A)
B)
C)
D)
182)
182)
A Category I furnace operates with a:
A)
High-temperature, positive-pressure vent.
B)
High-temperature, negative-pressure vent.
C)
Low-temperature, negative-pressure vent.
D)
Low-temperature, positive-pressure vent.
Answer:
B
Explanation:
A)
B)
C)
D)
48
183)
183)
The four categories of gas-fired furnaces are based on:
A)
Firing rate.
B)
Efficiency.
C)
Category of gas being burned.
D)
Flue gas temperature and pressure.
Answer:
D
Explanation:
A)
B)
C)
D)
184)
184)
Why are standard low-efficiency furnaces no longer manufactured?
A)
They cannot provide the minimum 80 percent AFUE required by DOT.
B)
The thermocouple flame safety devices they use have not been thoroughly field tested.
C)
The standing pilot flame safety devices were deemed too hazardous after several
technicians were electrocuted while changing a thermocouple.
D)
Thermocouples proved to be an unreliable technology.
Answer:
A
Explanation:
A)
B)
C)
D)
185)
185)
What is the purpose of the heat exchanger?
A)
To exchange the combustion gas for the circulating air in order to transfer heat into the
house
B)
To separate the combustion gas from the circulating air while transferring heat from the
combustion gas to the circulating air
C)
To separate the combustion gas from the circulating air while transferring heat from the
circulating air to the combustion gas
D)
To mix the combustion gas and the circulating air to transfer heat from the combustion gas
to the house
Answer:
B
Explanation:
A)
B)
C)
D)
186)
186)
A precisely drilled hole that controls the amount of gas entering a burner is called:
A)
A carburetor.
B)
An orifice.
C)
A gas jet.
D)
A metering device.
Answer:
B
Explanation:
A)
B)
C)
D)
49
187)
187)
Which of the following is TRUE about the installation of condensate pumps on high-efficiency
furnaces?
A)
A filter must always be installed on the pump.
B)
A high-pressure pump must be used.
C)
A pump must be approved for use with condensate.
D)
Any pump may be used.
Answer:
C
Explanation:
A)
B)
C)
D)
188)
188)
What type of vent is used with 80 percent Category I furnaces?
A)
Single-wall stainless steel
B)
PVC
C)
90 percent efficiency furnaces do not require a vent.
D)
Type B double-wall gas vent
Answer:
D
Explanation:
A)
B)
C)
D)
189)
189)
The temperature rise of a furnace is:
A)
The BTU rating of the furnace.
B)
The amount of temperature a furnace can add to a house.
C)
The temperature difference between the air entering the furnace and leaving the furnace.
D)
The difference between the flue gas temperature and the combustion air temperature.
Answer:
C
Explanation:
A)
B)
C)
D)
190)
190)
What safety function does the limit switch perform?
A)
It prevents the furnace from overheating.
B)
It allows for the escape of flue gases.
C)
It prevents buildup of gases.
D)
It protects the main control panel from electrical surges.
Answer:
A
Explanation:
A)
B)
C)
D)
50
191)
191)
Which of the following statements accurately describes silicon carbide?
A)
It is pliable and can be shaped easily.
B)
It is brittle and will break easily.
C)
It is durable and will not break easily.
D)
It is strong and can be installed easily.
Answer:
B
Explanation:
A)
B)
C)
D)
192)
192)
What is a redundant gas valve?
A)
A gas valve that is used in case the main valve quits working
B)
A gas valve that has no real purpose
C)
A gas valve that was once necessary on older furnaces but is no longer used
D)
A gas valve with two valves mechanically in series
Answer:
D
Explanation:
A)
B)
C)
D)
193)
193)
How many volts are sent to a furnace spark igniter?
A)
24 V
B)
120 V
C)
10,000 V
D)
240 V
Answer:
C
Explanation:
A)
B)
C)
D)
194)
194)
The major electrical loads in an induced-draft hot surface ignition furnace are:
A)
Induced-draft blower, indoor fan motor, the gas valve, the igniter.
B)
Limit switch, fan switch, and door switch.
C)
Sequencer, heat strips, limit switch, and circuit breaker.
D)
Igniter, flame sensor, and gas valve.
Answer:
A
Explanation:
A)
B)
C)
D)
51
195)
195)
What happens if a technician comes into contact with the spark-ignition circuit while it is
energized?
A)
The technician will cause the circuit to short out.
B)
The technician will possibly die.
C)
The technician will likely not notice the contact.
D)
The technician will experience great discomfort.
Answer:
D
Explanation:
A)
B)
C)
D)
196)
196)
How is the limit wired on a furnace that uses a line voltage limit?
A)
The limit is wired in series with the gas valve.
B)
The limit is wired in series with the transformer primary.
C)
The limit is wired in series with the transformer secondary.
D)
The limit is wired in series with the indoor fan motor.
Answer:
B
Explanation:
A)
B)
C)
D)
197)
197)
What is a draft pressure switch?
A)
A switch that senses when a vent pipe is connected to the flue outlet
B)
A switch that senses when the burners ignite
C)
A switch that senses when a building has air leaks
D)
A switch that senses when the vent is in a draft condition
Answer:
D
Explanation:
A)
B)
C)
D)
198)
198)
What is normally used for the ground terminal on a spark igniter?
A)
The white neutral wire supplying current to the furnace
B)
A separate ground rod
C)
The burner assembly
D)
Spark igniters do not require a ground because they operate on DC voltage.
Answer:
C
Explanation:
A)
B)
C)
D)
52
199)
199)
What pieces of information are necessary to use a manufacturer's gas manifold pressure chart?
A)
The altitude and gas heating value
B)
Length of gas line and firing rate
C)
The gas line length, number of burners, and firing rate
D)
The number of burners and furnace firing rate
Answer:
A
Explanation:
A)
B)
C)
D)
200)
200)
What size should the combustion air ducts be for a room with a 60,000 BTU/hr input furnace and a
16,000 BTU/hr water heater if the air is traveling through horizontal ducts?
A)
76,000/2,000 = 38 sq in free area each
B)
The size is irrelevant so long as there are combustion air vents.
C)
76,000/1,000 = 76 sq in free area each
D)
76,000/4,000 = 19 sq in free area each
Answer:
A
Explanation:
A)
B)
C)
D)
201)
201)
How does altitude affect the firing rate of a furnace?
A)
Higher altitudes have higher firing rates.
B)
Higher altitude causes inconsistent firing rates.
C)
Higher altitudes have lower firing rates.
D)
Altitude affects firing rates insignificantly.
Answer:
C
Explanation:
A)
B)
C)
D)
202)
202)
Compared to furnaces installed at lower altitudes, furnaces installed at higher altitudes:
A)
Have a lower firing rate.
B)
Heat up more quickly.
C)
Require a larger vent.
D)
Have a higher firing rate.
Answer:
A
Explanation:
A)
B)
C)
D)
53
203)
203)
What is the temperature rise of a furnace with a supply air temperature of 130°F and a return air
temperature of 75°F, operating in an ambient temperature of 50°F?
A)
75°F - 50°F = 25°F temperature rise
B)
130°F - 50°F = 80°F temperature rise
C)
130°F - 75°F = 55°F temperature rise
D)
50°F + 75°F = 125°F temperature rise
Answer:
C
Explanation:
A)
B)
C)
D)
204)
204)
What type of vent is used for category IV gas appliances?
A)
PVC vent
B)
Type B vent
C)
Type L vent
D)
Single-wall, galvanized metal vent
Answer:
A
Explanation:
A)
B)
C)
D)
205)
205)
How does the specific gravity of propane compare with the specific gravity of natural gas?
A)
The specific gravity of propane is greater than that of natural gas.
B)
The specific gravity of propane is not relevant to piping.
C)
The specific gravity of propane and natural gas are the same.
D)
The specific gravity of natural gas is greater than that of propane.
Answer:
A
Explanation:
A)
B)
C)
D)
206)
206)
The maximum required length in a piping table considers:
A)
The length of the pipe and appliance fittings.
B)
Only the length of the pipe from the appliance to the meter.
C)
Only the length of the pipe.
D)
The length of the pipe, including all fittings, valves, or obstructions.
Answer:
D
Explanation:
A)
B)
C)
D)
54
207)
207)
What is the purpose of the second line on a two-pipe oil delivery system?
A)
To allow smaller piping
B)
To allow two flow rates for two-stage oil burners
C)
To double the amount of oil that can be delivered and increase capacity
D)
To send the oil that was pumped but not burned back to the tank
Answer:
D
Explanation:
A)
B)
C)
D)
208)
208)
The pressure-reducing valve is responsible for:
A)
Adding makeup water to the boiler.
B)
Retrieving makeup water from the boiler.
C)
Controlling the hot-water circulator.
D)
Condensing water vapor.
Answer:
A
Explanation:
A)
B)
C)
D)
209)
209)
What is a distillate oil?
A)
Distillates are filtered to remove impurities.
B)
Distillates are bio-fuels manufactured from ethanol.
C)
A distillate is what is left after all the residuals have been vaporized.
D)
Distillates evaporate at relatively low temperatures.
Answer:
D
Explanation:
A)
B)
C)
D)
210)
210)
Modern residential oil furnaces sense the flames using:
A)
A thermal sensing stack switch.
B)
Ultraviolet light sensors.
C)
A cadmium sulfide cell.
D)
Flame rectification.
Answer:
C
Explanation:
A)
B)
C)
D)
55
211)
211)
An oil furnace heat exchanger is built:
A)
Like a clamshell.
B)
Like a drum.
C)
Like a tube in a serpentine shape.
D)
Oil furnaces do not require heat exchangers.
Answer:
B
Explanation:
A)
B)
C)
D)
212)
212)
The ignition transformer provides:
A)
8,000 to 15,000 volts DC to the electrodes.
B)
120 to 240 volts DC to the electrodes.
C)
8,000 to 15,000 volts AC to the electrodes.
D)
120 to 240 volts AC to the electrodes.
Answer:
C
Explanation:
A)
B)
C)
D)
213)
213)
Which part of the nozzle produces the correct firing rate?
A)
Cone
B)
Orifice
C)
Spray pattern
D)
Spray angle
Answer:
B
Explanation:
A)
B)
C)
D)
214)
214)
Which types of oil feed system are generally self-purging?
A)
Both one- and two-pipe systems require manual purging.
B)
One-pipe oil feed systems
C)
Two-pipe oil feed systems
D)
Both one- and two-pipe systems are self-purging.
Answer:
C
Explanation:
A)
B)
C)
D)
56
215)
215)
What is used to clean the surfaces of the heat exchanger?
A)
Wire brush
B)
Razor blade
C)
Abrasive sponge
D)
Soft cloth
Answer:
A
Explanation:
A)
B)
C)
D)
216)
216)
The flow resistance through the heat exchanger of an oil furnace is frequently increased because
of:
A)
Soot accumulation.
B)
Water accumulation.
C)
Internal collapse of the heat exchanger.
D)
Loose heat exchanger cross-baffle members.
Answer:
A
Explanation:
A)
B)
C)
D)
217)
217)
Compared to the over-fire draft, the stack draft should be:
A)
Less negative than the over-fire draft.
B)
A positive pressure.
C)
About the same as the over-fire draft.
D)
More negative than the over-fire draft.
Answer:
D
Explanation:
A)
B)
C)
D)
218)
218)
The output of an oil furnace ignition transformer can be tested:
A)
Using a voltmeter that can read 1,000 V AC.
B)
Using a voltmeter that can read 1,000 V DC.
C)
With a special high-voltage probe that reduces the voltage to a level a standard meter can
read.
D)
Using the microamp scale on a multimeter.
Answer:
C
Explanation:
A)
B)
C)
D)
57
219)
219)
What advantage is there to maintaining a negative pressure on the heat exchanger?
A)
Combustion air can only be drawn into the oil burner if a negative pressure is maintained.
B)
The negative pressure helps draw in return air from the house, increasing efficiency.
C)
Safety; it ensures combustion products do not leak out into the air stream.
D)
The vent will not work unless the heat exchanger is at a negative pressure.
Answer:
C
Explanation:
A)
B)
C)
D)
220)
220)
The normal fan switch on temperature range is:
A)
8590°F.
B)
125130°F.
C)
95100°F.
D)
140150°F.
Answer:
B
Explanation:
A)
B)
C)
D)
221)
221)
How much vacuum must a fuel oil pump produce to lift fuel oil up 6 ft?
A)
6 ÷ 3 = 2 in of vacuum
B)
6 × 2 = 12 in of vacuum
C)
6 × 1 = 6 in of vacuum
D)
6 ÷ 2 = 3 in of vacuum
Answer:
C
Explanation:
A)
B)
C)
D)
222)
222)
How much vacuum must a fuel oil pump produce to move fuel oil 20 ft horizontally?
A)
20 ÷ 2 = 10 in of vacuum
B)
20 × 1 = 20 in of vacuum
C)
20 ÷ 5 = 4 in of vacuum
D)
20 ÷ 10 = 2 in of vacuum
Answer:
D
Explanation:
A)
B)
C)
D)
58
223)
223)
What is the equivalent length of a 5-in connector with a 90-degree ell?
A)
7 ft
B)
9 ft
C)
11 ft
D)
5 ft
Answer:
B
Explanation:
A)
B)
C)
D)
224)
224)
Which is a primary safety requirement when replacing an older furnace?
A)
Properly discarding used materials
B)
Relocating the thermostat
C)
Properly grounding the furnace cabinet
D)
Removing the jumper
Answer:
C
Explanation:
A)
B)
C)
D)
225)
225)
Where should the barometric damper be installed in the chimney connector?
A)
Close to the furnace in series with the connector so that the vent gases must pass through it
B)
Close to the furnace on the bull head of a tee that is in-line with the connector
C)
On the outlet of the chimney so that the vent gases must pass through it
D)
Close to the furnace on the branch of a tee that is in-line with the connector
Answer:
D
Explanation:
A)
B)
C)
D)
226)
226)
What type of oil delivery system is recommended when the vacuum required for lifting the oil
from the tank to the furnace is 16 in Hg?
A)
A two-pipe oil delivery system with a single-stage oil pump
B)
A single-pipe oil delivery system with a single-stage pump
C)
A two-pipe oil delivery system with a two-stage oil pump
D)
A single-pipe oil delivery system with a two-stage oil pump
Answer:
C
Explanation:
A)
B)
C)
D)
59
227)
227)
When exposed to light, the resistance of a good cad cell should be:
A)
5,000 to 10,000.
B)
100,000 or higher.
C)
30 to 1,000.
D)
1,000 to 5,000.
Answer:
C
Explanation:
A)
B)
C)
D)
228)
228)
If the pump cutoff is working properly, the output pressure should not drop past what percentage
below the operating pressure?
A)
40 percent
B)
10 percent
C)
30 percent
D)
20 percent
Answer:
D
Explanation:
A)
B)
C)
D)
229)
229)
To ensure correct operation, how often should the nozzle be replaced?
A)
Every 18 months
B)
Every 3 years
C)
Every year
D)
Every 6 months
Answer:
C
Explanation:
A)
B)
C)
D)
230)
230)
If the resistance of the cad cell is too high, you should:
A)
Close the circuit.
B)
Repair the cad cell.
C)
Replace the cad cell.
D)
Reset the switch.
Answer:
C
Explanation:
A)
B)
C)
D)
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