231)
231)
Why should circuits that are locked out also be tagged?
A)
To notify the customer where they can pay their bill
B)
As backup to prevent people from cutting the lock off and turning the power on
C)
To provide instructions for re–energizing the circuit
D)
To identify who has the circuit locked out
Answer:
D
Explanation:
A)
B)
C)
D)
232)
232)
A technician is contacting a live circuit with one hand and is not being shocked. However, they
can receive an electrical shock:
A)
If they fail to ground themselves.
B)
If they touch the same live wire with both hands.
C)
When they release the electrical wire.
D)
If they ground themselves.
Answer:
D
Explanation:
A)
B)
C)
D)
233)
233)
What use is THHN wire suitable for?
A)
Underground burial
B)
Wet or oily locations
C)
Dry locations only
D)
Dry or damp locations
Answer:
D
Explanation:
A)
B)
C)
D)
234)
234)
What tool is used to remove cartridge fuses from a fused disconnect box?
A)
Pliers with an insulated handle
B)
A screwdriver
C)
No tools are necessaryjust reach in and pull the fuse out.
D)
A fuse puller
Answer:
D
Explanation:
A)
B)
C)
D)
61
235)
235)
If the technician encounters a circuit breaker that is tripping repeatedly, she should first:
A)
Find the electrical fault that is causing the breaker to trip.
B)
Keep resetting the breaker until something fails.
C)
Replace the breaker with one with a higher rating.
D)
Bypass the breaker.
Answer:
A
Explanation:
A)
B)
C)
D)
236)
236)
The American Wire Gauge rates wires in size from smallest to largest as:
A)
50 to 0000.
B)
000 to 50.
C)
4 mm to 40 mm.
D)
40 mm to 4 mm.
Answer:
A
Explanation:
A)
B)
C)
D)
237)
237)
Which wire can carry a higher current?
A)
AWG 6
B)
AWG 24
C)
AWG 12
D)
AWG 18
Answer:
A
Explanation:
A)
B)
C)
D)
238)
238)
The types of injury electricity can inflict on a person include:
A)
Electrical shock.
B)
Electrical burns.
C)
Electricity cannot inflict injury.
D)
Electrical shock and burns.
Answer:
D
Explanation:
A)
B)
C)
D)
62
239)
239)
The safest category of electric meters is:
A)
Category I.
B)
Category II.
C)
Category III.
D)
Category IV.
Answer:
D
Explanation:
A)
B)
C)
D)
240)
240)
Which of the following devices can detect when a technician is receiving an electrical shock and
turn off the power?
A)
A fuse
B)
A GFCI
C)
A circuit breaker
D)
Fuses, circuit breakers, and GFCI devices can all detect when a person is receiving a shock.
Answer:
B
Explanation:
A)
B)
C)
D)
241)
241)
Category II electric meters are safe for working on which types of circuits?
A)
The power lines coming into the meter base outside the house
B)
The circuits inside an appliance that plugs into a 120–volt receptacle
C)
Inside the breaker panel inside the house
D)
The disconnect on an outdoor air–conditioning unit
Answer:
B
Explanation:
A)
B)
C)
D)
242)
242)
When a circuit breaker trips:
A)
The breaker is in the middle and is not in the off or on position.
B)
The breaker switch moves from the on position to the off position.
C)
A yellow indicator light shows that it has tripped.
D)
The breaker pops out of the panel.
Answer:
A
Explanation:
A)
B)
C)
D)
63
243)
243)
What is the best tool for determining if an electrical wire running through a space where you are
working is energized?
A)
A clamp–on voltmeter
B)
A digital voltmeter
C)
A noncontact voltage detector
D)
A multimeter
Answer:
C
Explanation:
A)
B)
C)
D)
244)
244)
The outer scale on most gauges reads:
A)
Pressure.
B)
Weight.
C)
Saturation temperature.
D)
Compound temperature.
Answer:
A
Explanation:
A)
B)
C)
D)
245)
245)
The high–pressure gauge reads:
A)
The pressures on both the low side and the high side of the system.
B)
Only pressures above atmospheric pressure.
C)
Only pressures below atmospheric pressure.
D)
Pressures above and below atmospheric pressure.
Answer:
B
Explanation:
A)
B)
C)
D)
246)
246)
The temperature measurement of the air outside around the unit is called:
A)
Supply–air temperature.
B)
Return–air temperature.
C)
Ambient temperature.
D)
Approach temperature.
Answer:
C
Explanation:
A)
B)
C)
D)
64
247)
247)
Why is a large refrigerant leak potentially dangerous?
A)
Most common refrigerants used in residential systems are highly toxic.
B)
Most common refrigerants used in residential systems are highly corrosive.
C)
Most common refrigerants used in residential systems are highly flammable.
D)
They can replace all of the oxygen, leading to asphyxiation.
Answer:
D
Explanation:
A)
B)
C)
D)
248)
248)
Which of the following is the most reliable and inexpensive thermometer used by technicians?
A)
Dial
B)
Digital
C)
Glass–stem
D)
Infrared
Answer:
C
Explanation:
A)
B)
C)
D)
249)
249)
The low–side gauge is called:
A)
A compound gauge.
B)
A vacuum gauge.
C)
A cold gauge.
D)
A high–pressure gauge.
Answer:
A
Explanation:
A)
B)
C)
D)
250)
250)
Positive shutoff fittings allow technicians to reduce the amount of which of the following?
A)
Refrigerant spray when connecting to a refrigeration system
B)
Liquid in the unit during evacuation
C)
The amount of refrigerant coming into the hoses
D)
Refrigerant spray when disconnecting from a refrigeration system
Answer:
D
Explanation:
A)
B)
C)
D)
65
251)
251)
What color surface temperature can be read most accurately with an infrared thermometer?
A)
Infrared thermometers are not affected by the color of the surface being measured.
B)
Light–colored, dull surfaces are best because they will radiate infrared light instead of
absorbing it.
C)
Shiny surfaces work best because they reflect infrared light better.
D)
The closest to a flat black
Answer:
D
Explanation:
A)
B)
C)
D)
252)
252)
The temperature measurement of the air entering the air intake grille is called:
A)
Supply–air temperature.
B)
Return–air temperature.
C)
Ambient temperature.
D)
Approach temperature.
Answer:
B
Explanation:
A)
B)
C)
D)
253)
253)
If one needs to know the temperature in a hard place to reach and accuracy is not a top priority,
which thermometer should be used?
A)
Dial
B)
Glass–stem
C)
Digital
D)
Infrared
Answer:
D
Explanation:
A)
B)
C)
D)
254)
254)
What color hose is used for connecting to the charging refrigerant cylinder vacuum pump or the
recovery machine?
A)
Red
B)
Black
C)
Blue
D)
Yellow
Answer:
D
Explanation:
A)
B)
C)
D)
66
255)
255)
Which of the following is a thermometer used to measure the temperature of objects without
physically touching them?
A)
Glass–stem
B)
Infrared
C)
Dial
D)
Digital
Answer:
B
Explanation:
A)
B)
C)
D)
256)
256)
The smallest incremental markings on analog gauges designed for R–410A are generally:
A)
20 psi.
B)
5 psi.
C)
1 psi.
D)
10 psi.
Answer:
B
Explanation:
A)
B)
C)
D)
257)
257)
Which torch type would be the best choice for a brazing project?
A)
Air–fuel torch
B)
Oxyacetylene torch
C)
Air–propane swirl–tip torch
D)
Air–MAPP swirl–tip torch
Answer:
B
Explanation:
A)
B)
C)
D)
258)
258)
Why might closing the oxygen cylinder, then the acetylene cylinder, then bleeding first the oxygen
line, then finally the acetylene line at the end of a brazing project create a hazardous situation?
A)
The acetylene and oxygen cylinders should be closed simultaneously.
B)
The last gas to go through the torch will be a flammable gas.
C)
The acetylene and oxygen lines should be bled simultaneously.
D)
The acetylene cylinder should be closed first.
Answer:
B
Explanation:
A)
B)
C)
D)
67
259)
259)
The correct shutoff procedure for an oxyacetylene torch is:
A)
Place the torch tip under water until it extinguishes and then shut off the torch valves.
B)
Close the oxygen first and then the acetylene.
C)
Close the oxygen and acetylene simultaneously.
D)
Close the acetylene first and then the oxygen.
Answer:
B
Explanation:
A)
B)
C)
D)
260)
260)
How many cubic feet of acetylene gas is stored in a size MC acetylene tank weighing 8.0 pounds?
A)
7.5 ft3
B)
10 ft3
C)
5 ft3
D)
0 ft3
Answer:
B
Explanation:
A)
B)
C)
D)
261)
261)
The outside of a soldered joint looks complete, but when it is cut open for testing, the solder has
not flowed into the joint. What may have happened to cause this?
A)
The pipe was heated before the joint.
B)
The pipe was overheated.
C)
The wrong type of solder was used.
D)
The joint was heated before the pipe.
Answer:
D
Explanation:
A)
B)
C)
D)
262)
262)
Which of the following statements is TRUE?
A)
All soldering alloys containing copper do not require flux.
B)
All brazing alloys containing phosphorus require flux.
C)
All brazing alloys containing phosphorus do not require flux.
D)
Soldering alloys have a higher flow temperature than brazing alloys.
Answer:
C
Explanation:
A)
B)
C)
D)
68
263)
263)
The safety cap should always be in place when moving oxygen cylinders because:
A)
The safety cap prevents oxygen from leaking out.
B)
The safety cap provides a good place to connect a hook for lifting the cylinder.
C)
The safety cap prevents cylinder overpressurization.
D)
If the valve were to break off, the cylinder would fly through the air.
Answer:
D
Explanation:
A)
B)
C)
D)
264)
264)
Which of the following articles of clothing is a potential safety hazard when soldering?
A)
Heavy cotton shirt
B)
Leather gloves
C)
Rayon–polyester running pants
D)
Denim blue jeans
Answer:
C
Explanation:
A)
B)
C)
D)
265)
265)
Why are copper fittings cleaned before soldering or brazing?
A)
To remove oxides
B)
To enhance the aesthetic appearance of the completed joint
C)
To make it easier to see the junction between the fitting and the pipe
D)
To create enough clearance so that the pipe will fit into the fitting
Answer:
A
Explanation:
A)
B)
C)
D)
266)
266)
What is a potential complication that is unique to brazing?
A)
Improper cleaning of the pipe can reduce bonding.
B)
Overheating the pipe can result in leakage.
C)
Heating the joint before the pipe can result in an improper fit.
D)
Overheating the pipe can result in excessive oxidation.
Answer:
D
Explanation:
A)
B)
C)
D)
69
267)
267)
What is the proper heating procedure for soldering?
A)
Heat the pipe first and then the joint.
B)
Place the solder on the joint and melt it with the flame.
C)
Heat the joint first and then the pipe.
D)
Heat the solder first and then the joint.
Answer:
A
Explanation:
A)
B)
C)
D)
268)
268)
What is the purpose of the acetylene and oxygen regulators?
A)
To boost the gas pressure from the tank pressures to the pressures used by the torch
B)
To make turning the torches on and off more convenient
C)
To provide an automatic safety shutoff in case of emergencies
D)
To reduce the tank pressures and maintain a steady pressure to the torch
Answer:
D
Explanation:
A)
B)
C)
D)
269)
269)
The factors that must be considered when sizing the discharge line are:
A)
Pressure drop and velocity.
B)
Temperature rise and refrigerant viscosity.
C)
Temperature rise and oil viscosity.
D)
Pressure drop, temperature rise, velocity, and oil viscosity.
Answer:
A
Explanation:
A)
B)
C)
D)
70
270)
270)
What is an oil lift?
A)
An oil lift helps return oil up a vertical riser using an integral orifice tube, which creates a
Bernoulli effect, forcing oil up the line.
B)
An oil lift is the increase in pressure created in the suction line due to the presence of
refrigerant oil.
C)
An oil lift is an electric oil pump that moves collected refrigerant oil up against gravity.
D)
An oil lift is a trap at the bottom of a vertical suction riser.
Answer:
D
Explanation:
A)
B)
C)
D)
271)
271)
What is considered a long–line application for residential air conditioning?
A)
Lines exceeding 80 ft in length or with a vertical rise of more than 20 ft
B)
Lines exceeding 50 ft in length or with a vertical rise of more than 10 ft
C)
Lines exceeding 100 ft in length or with a vertical rise of more than 30 ft
D)
Air–conditioning systems can run lines for nearly any length with no problems.
Answer:
A
Explanation:
A)
B)
C)
D)
272)
272)
Undersized suction lines:
A)
Can cause poor oil return because of high refrigerant velocity.
B)
Can reduce system efficiency because of a low pressure drop.
C)
Can reduce system efficiency because of a high pressure drop.
D)
Can cause poor oil return because of low refrigerant velocity.
Answer:
C
Explanation:
A)
B)
C)
D)
273)
273)
Why is it necessary to purge gauge manifold valves while they are connected?
A)
To preserve the system’s charge
B)
To stop refrigerant loss
C)
To prevent contamination of the system
D)
To prevent valve damage
Answer:
C
Explanation:
A)
B)
C)
D)
71
274)
274)
The stems on manual stem service valves should be turned with:
A)
Either a refrigeration service valve wrench or an adjustable jaw wrench.
B)
Either a refrigeration service valve wrench or a pair of pliers.
C)
Either an adjustable jaw wrench or a pair of pliers.
D)
A refrigeration service valve wrench only.
Answer:
D
Explanation:
A)
B)
C)
D)
275)
275)
Commercial refrigeration systems normally have:
A)
Most commercial refrigeration systems do not have refrigeration service valves.
B)
A suction service valve, a discharge service valve, and a king valve.
C)
A liquid line valve and a suction service valve.
D)
A suction service valve and a discharge service valve.
Answer:
B
Explanation:
A)
B)
C)
D)
276)
276)
Why are positive shutoff devices used when removing gauge manifold sets from Schrader valves?
A)
To restart the system for installation
B)
To prevent postremoval refrigerant venting
C)
To reduce the release of refrigerants
D)
To automatically loosen Schrader valves
Answer:
C
Explanation:
A)
B)
C)
D)
277)
277)
Which is the primary purpose of a split–system installation valve‘s service port?
A)
Trapping refrigerant
B)
System evacuation
C)
Controlling leaks
D)
Valve maintenance
Answer:
B
Explanation:
A)
B)
C)
D)
72
278)
278)
What types of system access valves do household refrigerators usually have?
A)
Manual valves on the compressor suction and discharge and on the liquid receiver
B)
Schrader valves on the compressor suction and discharge and on the liquid receiver
C)
Schrader valves on the suction line and liquid line
D)
A process stub on the compressor
Answer:
D
Explanation:
A)
B)
C)
D)
279)
279)
How do piercing pliers differ from braze–on piercing valves with regard to how they are used on
sealed systems?
A)
Piercing pliers require a bolted valve.
B)
Piercing pliers cannot be a permanent solution.
C)
Piercing pliers cannot be used to recover refrigerant.
D)
Piercing pliers have a greater danger of causing overheating.
Answer:
B
Explanation:
A)
B)
C)
D)
280)
280)
Which refrigeration hose end has a Schrader valve core depressor?
A)
The angled end
B)
Both ends have a core depressor.
C)
The straight end
D)
Neither end has a core depressor.
Answer:
A
Explanation:
A)
B)
C)
D)
281)
281)
When a manual service valve is frontseated:
A)
Both the service port and the line are closed to the system.
B)
Both the service port and the line are open to the system.
C)
The service port is open and the system is closed to the line.
D)
The service port is closed and the system is open to the line.
Answer:
C
Explanation:
A)
B)
C)
D)
73
282)
282)
What types of system access valves do commercial refrigeration systems usually have?
A)
Manual valves on the compressor suction and discharge and on the liquid receiver
B)
Schrader valves on the compressor suction and discharge and on the liquid receiver
C)
Schrader valves on the suction line and liquid line
D)
A process stub on the compressor
Answer:
A
Explanation:
A)
B)
C)
D)
283)
283)
A normal operational refrigerant release would be:
A)
Venting refrigerant to correct an overcharge.
B)
Releasing the charge to change the metering device.
C)
Venting the charge to change a compressor.
D)
Releases from purge cycle operation.
Answer:
D
Explanation:
A)
B)
C)
D)
284)
284)
Why is the push–pull method of recovery preferable for some systems with large quantities of
refrigerant?
A)
It does not require certification.
B)
It recovers the greatest amount.
C)
It is the quickest method.
D)
It requires no special equipment.
Answer:
C
Explanation:
A)
B)
C)
D)
285)
285)
Why are some reclaimed refrigerants classified as hazardous materials?
A)
They are from pre–1993 systems.
B)
They may contain corrosive or carcinogenic chemicals.
C)
They have been through sealed systems.
D)
They have been recycled before being reclaimed.
Answer:
B
Explanation:
A)
B)
C)
D)
74
286)
286)
The four parts of the EPA Certification exam include:
A)
Core, Type I– small appliances, Type II– medium–duty appliances, and Type III– large
appliances.
B)
Core, Type I– small appliances, Type II– residential appliances, and Type III– commercial
and industrial appliances.
C)
Level I, Level II, Level III, and Universal.
D)
Core, Type I– small appliances, Type II– high–pressure and very high–pressure appliances,
and Type III– low–pressure appliances.
Answer:
D
Explanation:
A)
B)
C)
D)
287)
287)
How is MVAC certification established?
A)
Through universal certification
B)
Through lack of certification
C)
Through separate certification
D)
Through any type of certification
Answer:
C
Explanation:
A)
B)
C)
D)
288)
288)
Refrigerant that has been reprocessed to at least the purity specified in ARI Standard 700 is
considered:
A)
Recovered refrigerant.
B)
Recycled refrigerant.
C)
Reclaimed refrigerant.
D)
Virgin refrigerant.
Answer:
C
Explanation:
A)
B)
C)
D)
289)
289)
In which way did Title VI, Section 608 of the Clean Air Act additionally regulate refrigerant
technicians?
A)
It eliminated prior refrigerant standards.
B)
It banned the disposal of ozone–depleting units.
C)
It limited their abilities to repair most units.
D)
It required that they hold a certification.
Answer:
D
Explanation:
A)
B)
C)
D)
75
290)
290)
When connecting a recovery system for push–pull liquid recovery, the outlet of the recovery unit
is connected to:
A)
The king valve on the system.
B)
The discharge service valve on the system.
C)
The vapor valve on the refrigerant recovery cylinder.
D)
The liquid valve on the refrigerant recovery cylinder.
Answer:
B
Explanation:
A)
B)
C)
D)
291)
291)
To prevent the system refrigerant from quickly dropping in temperature and pressure, refrigerant
recovery should:
A)
Only be attempted in the summer.
B)
Always take place while the system is operating.
C)
Begin with liquid.
D)
Begin with vapor.
Answer:
C
Explanation:
A)
B)
C)
D)
292)
292)
The maximum safe pressure to impose on any low–pressure system is:
A)
15 psig.
B)
5 psig.
C)
20 psig.
D)
10 psig.
Answer:
D
Explanation:
A)
B)
C)
D)
293)
293)
How does dye indicate system leaks?
A)
The dye highlights small cracks when rubbed over the outside of the joint.
B)
The dye reacts with the refrigerant, making the inside of the system glow.
C)
Dye gives the refrigerant a color, so it looks like a psychedelic cloud escaping from the
system.
D)
Dye makes the refrigerant oil spots more visible.
Answer:
D
Explanation:
A)
B)
C)
D)
76
294)
294)
If the low–side test pressure is not known, the maximum pressure that should be used for leak
testing an R–22 refrigeration system with hermetic compressor is:
A)
300 psig.
B)
200 psig.
C)
250 psig.
D)
150 psig.
Answer:
D
Explanation:
A)
B)
C)
D)
295)
295)
How are trigger rates established?
A)
By total annual loss
B)
By amount of coolant capacity
C)
By speed of loss
D)
By total monthly loss
Answer:
C
Explanation:
A)
B)
C)
D)
296)
296)
Leaks on the low side of a Type III system are indicated by:
A)
Puddles of refrigerant on the floor around the machine.
B)
Lower–than–normal system pressures.
C)
Oil stains around the leak from oil carried with the leaking refrigerant.
D)
Increased purge operation.
Answer:
D
Explanation:
A)
B)
C)
D)
297)
297)
Which of the following is an indicator of a leaking refrigerant system?
A)
Front–seated system valves
B)
Visible line bracing
C)
Higher–than–normal temperature readings
D)
Metal–to–metal contact points
Answer:
D
Explanation:
A)
B)
C)
D)
77
298)
298)
Leaks in commercial refrigeration systems must be repaired if they have an annual leak rate of:
A)
10 percent of the charge per year.
B)
15 percent of the charge per year.
C)
25 percent of the charge per year.
D)
35 percent of the charge per year.
Answer:
D
Explanation:
A)
B)
C)
D)
299)
299)
What is the annual leak rate of a system that holds 100 lb of refrigerant and loses three lb of
refrigerant in a month?
A)
You must check for an entire year to calculate the annual leak rate.
B)
36 percent
C)
3 percent
D)
The annual leak rate can only be determined at the factory.
Answer:
B
Explanation:
A)
B)
C)
D)
300)
300)
Once acid is created within the refrigeration system:
A)
It becomes impossible to remove brazing oxides and metal particles from the system, even if
a filter drier is used.
B)
Dry nitrogen must be used to reverse the increase in system high–side pressure caused by
the acid.
C)
It can cause a burnout when the refrigerant is exposed to the compressor motor.
D)
Only a multiple evacuation procedure can be used to evacuate the refrigeration system.
Answer:
C
Explanation:
A)
B)
C)
D)
301)
301)
To speed up evacuation, you should use:
A)
Large–diameter, long hoses.
B)
Small–diameter, long hoses.
C)
Small–diameter, short hoses.
D)
Large–diameter, short hoses.
Answer:
D
Explanation:
A)
B)
C)
D)
78
302)
302)
Which of the following is actually being measured when a vacuum is measured in microns?
A)
The amount of pressure that has been removed from the system
B)
The amount of pressure that remains in the system
C)
The full atmospheric pressure at sea level in the system
D)
The difference between the atmospheric pressure and mercury
Answer:
B
Explanation:
A)
B)
C)
D)
303)
303)
A micron is a unit of length equal to:
A)
1/1,000 of a kilometer.
B)
1/1,000 of a meter.
C)
1/1,000 of a inch.
D)
1/1,000 of a millimeter.
Answer:
D
Explanation:
A)
B)
C)
D)
304)
304)
When using a three–port manifold, the vacuum pump should be connected to:
A)
The middle port of a standard three–port manifold.
B)
The compressor.
C)
The evaporator coil, only if the Schrader value has been removed.
D)
The suction line service valve.
Answer:
A
Explanation:
A)
B)
C)
D)
305)
305)
Microns are used to measure deep vacuum by measuring:
A)
The amount of pressure that has been removed.
B)
The height of a column of mercury supported by the remaining absolute pressure.
C)
The number of molecules remaining in the evacuated space.
D)
The distance between the remaining molecules.
Answer:
B
Explanation:
A)
B)
C)
D)
79
306)
306)
In general, a system that is overcharged will have:
A)
A low subcooling and a low superheat.
B)
A high subcooling and a low superheat.
C)
A low subcooling and a high superheat.
D)
A high subcooling and a high superheat.
Answer:
B
Explanation:
A)
B)
C)
D)
307)
307)
Which of the following types of charge is usually employed when a partial charge is required?
A)
Vapor
B)
Negative
C)
Liquid
D)
Positive
Answer:
A
Explanation:
A)
B)
C)
D)
308)
308)
Why must zeotropic refrigerant leave the cylinder as a liquid?
A)
To reduce the risk of noncondensables entering the system
B)
To avoid fractionation
C)
To keep the pressure in the cylinder at a safe level
D)
To avoid condensation
Answer:
B
Explanation:
A)
B)
C)
D)
309)
309)
An air–conditioning system charged with R–410A is operating with a suction pressure of 130 psig,
which equates to a 45°F saturation temperature. If the manufacturer calls for a 15°F superheat,
what should the suction line temperature be?
A)
130 psig – 15°F = 115°F suction line temperature
B)
130 psig + 15°F = 190°F suction line temperature
C)
45°F – 15°F = 30°F suction line temperature
D)
45°F + 15°F = 60°F suction line temperature
Answer:
D
Explanation:
A)
B)
C)
D)
80