81)
81)
Why are face shields worn during arc welding?
A)
To magnify the work area and make it easier to see
B)
To keep the technician from breathing in harmful fumes
C)
Face shields are not necessary when arc welding.
D)
To protect technicians from strong ultraviolet (UV) light
Answer:
D
Explanation:
82)
82)
What equipment that is NOT required by other torches is required to operate an oxyacetylene
torch?
A)
Hose to connect the regulator to the handle
B)
Oxygen cylinder
C)
Acetylene cylinder
D)
Regulator for the acetylene cylinder
Answer:
B
Explanation:
83)
83)
What can happen if you do not purge with nitrogen while brazing?
A)
You run the risk of an explosion.
B)
The brazing will take longer without the extra heat from the nitrogen.
C)
Leak checking will take longer.
D)
Oxides inside the pipe can come loose and contaminate the system.
Answer:
D
Explanation:
84)
84)
Why are the stubs on compressors and filter driers more difficult to braze than copper pipe?
A)
They have a thin copper coating that is easily oxidized by overheating.
B)
They are difficult to get to.
C)
They are typically made of aluminum, which is much harder to braze.
D)
It is easy to burn a hole in the compressor or drier shell.
Answer:
A
Explanation:
21
85)
85)
What type of thread lubricant should be used when connecting the oxygen regulator to the oxygen
cylinder?
A)
Light–weight machine oil
B)
Only nonflammable packing
C)
Teflon tape
D)
No lubricant or sealant of any kind should be used.
Answer:
D
Explanation:
86)
86)
What is the advantage of an oxyacetylene torch compared to an air acetylene torch?
A)
It is a more intense flame that heats up the parts faster than air acetylene flames.
B)
Oxyacetylene equipment is simpler.
C)
Oxyacetylene flames cannot form carbon.
D)
Unlike acetylene torches, oxyacetylene torches do not oxidize metal when heating it.
Answer:
A
Explanation:
87)
87)
How can technicians protect themselves from hot sparks produced by most welding processes?
A)
Use welding rods that prevent the formation of sparks.
B)
Wear heavy protective clothing, gloves, and eye protection.
C)
Use a spark arrestor to prevent any sparks from occurring during the welding process.
D)
Wear light weight clothing made from synthetic material.
Answer:
B
Explanation:
88)
88)
How do you know when to stop applying solder?
A)
The solder will run out of the top of the joint when it is full.
B)
The solder will stop flowing into the joint.
C)
The solder will draw all the way around the joint.
D)
When solder balls form on both sides of the joint, you are done.
Answer:
C
Explanation:
22
89)
89)
Why might adjusting the oxygen flow during a brazing project by standing in front of the cylinder
and slowly opening the valve all the way create a hazardous situation?
A)
The valve should only be opened halfway.
B)
The valve should be opened quickly to relieve pressure.
C)
The valve should be opened while standing behind the cylinder.
D)
The valve should only be opened two–and–a–half turns.
Answer:
C
Explanation:
90)
90)
Why is it recommended that an acetylene cylinder valve never be opened more than one–half
turn?
A)
To regulate the pressure to the torch handle
B)
To allow rapid shutoff in the case of an accident
C)
To minimize the strain of the high cylinder pressures on the valve threads
D)
To prevent the valve from getting stuck in the fully opened position
Answer:
B
Explanation:
91)
91)
Most air–conditioning manufacturers specify that refrigerant lines should be:
A)
Glued.
B)
Brazed.
C)
Soldered.
D)
Welded.
Answer:
B
Explanation:
92)
92)
What material should clothes worn during welding be made of?
A)
A polyester, nylon, acetate blend
B)
65% polyester, 35% nylon
C)
100% polyester
D)
100% cotton
Answer:
D
Explanation:
23
93)
93)
What is the purpose of purging with nitrogen while brazing?
A)
To help the flame burn a little hotter
B)
To blow the oxides off the walls before it has a chance to firmly adhere
C)
To prevent oxide formation inside the pipes
D)
To check for leaks at the same time you are brazing
Answer:
C
Explanation:
94)
94)
When brazing on a refrigeration line with an attached service valve:
A)
The joint should be heated slowly to prevent overheating the valve.
B)
The joint should be heated quickly to avoid overheating the valve.
C)
The valve should be cut out of the system prior to brazing to avoid overheating.
D)
The line should be attached with quick–setting cement instead of brazed.
Answer:
B
Explanation:
95)
95)
The solder should be melted:
A)
After wrapping it around the pipe.
B)
By the torch flame.
C)
By touching it to the pipe.
D)
Before applying the flame to the pipe.
Answer:
C
Explanation:
96)
96)
At what temperature does brazing take place?
A)
Above 840°F
B)
Less than 400°F
C)
Above 1,800°F
D)
Less than 840°F
Answer:
A
Explanation:
24
97)
97)
To avoid being injured by a catastrophic regulator failure, when cracking open the oxygen
cylinder you should stand:
A)
Behind the valve by the T handle.
B)
In front of the valve on the same side of the T handle.
C)
Directly in front of the T handle so you can turn it off quickly.
D)
Behind the valve on the opposite side of the T handle.
Answer:
D
Explanation:
98)
98)
Why might wearing safety glasses with a shade of 11 create a hazardous situation?
A)
Smooth–toed leather shoes are not adequate for soldering.
B)
Shade 11 glasses may obscure vision while soldering.
C)
Smooth–toed leather shoes can trap sparks and debris.
D)
Shade 11 glasses are not adequate for soldering.
Answer:
B
Explanation:
99)
99)
Which of the following statements is accurate?
A)
Nitrogen flow should be kept at design pressure while brazing.
B)
Nitrogen flow must be kept at 50 psig while brazing.
C)
Nitrogen should not be in the system while brazing.
D)
Nitrogen flow must be kept below 2 psig while brazing.
Answer:
D
Explanation:
25
100)
100)
Why might opening the acetylene cylinder‘s square stem valve three–and–a–half turns with a
wrench and leaving the wrench on the valve while working create a hazardous situation?
A)
The valve should be opened less than two–and–a–half turns.
B)
The wrench should not be used on a square stem valve.
C)
The valve should be opened at least four turns to minimize internal pressure.
D)
The wrench should be removed from the valve while soldering.
Answer:
A
Explanation:
101)
101)
The correct lighting procedure for an oxyacetylene torch is:
A)
Fully open both the acetylene and oxygen, wait 30 seconds, and then light the mixture.
B)
Crack the acetylene and light it first, then add the oxygen.
C)
Crack the oxygen and light it first, then add the acetylene.
D)
Crack both the acetylene and oxygen and light the mixture.
Answer:
B
Explanation:
102)
102)
Liquid lines need to be insulated:
A)
For systems using HFC refrigerants.
B)
If they are run close enough to the hot suction line to pick up heat from it.
C)
If they travel through an unusually hot space.
D)
Always.
Answer:
C
Explanation:
103)
103)
Refrigerant oil flow through the liquid line is not a problem because:
A)
The oil and refrigerant do not mix, so the refrigerant does not interfere with oil flow.
B)
There is no oil present in the liquid line.
C)
The oil mixes with the liquid refrigerant.
D)
The liquid line is always piped downhill.
Answer:
C
Explanation:
26
104)
104)
An R–22 system has a 6 psi pressure drop in the liquid line and leaves the condenser at 218 psi. If
the pressure at the top of the vertical lift is 199 psi, what is the height of the vertical lift?
A)
21 ft
B)
29 ft
C)
19 ft
D)
26 ft
Answer:
D
Explanation:
105)
105)
One difference between refrigerant piping practices for air–conditioning systems and refrigerant
piping practices for commercial refrigeration systems is that:
A)
Suction lines are typically larger for air–conditioning applications for the same capacity of
commercial refrigeration systems.
B)
Most air–conditioning manufacturers do not recommend oil traps.
C)
The suction lines on air–conditioning systems do not require insulating because of their
higher temperature.
D)
Most commercial refrigeration system manufacturers do not recommend oil traps.
Answer:
B
Explanation:
106)
106)
Oil accumulation in the evaporator:
A)
Can lead to leaks because refrigerant oil is corrosive to the metal used in evaporator coils.
B)
Helps lubricate the walls of the evaporator.
C)
Improves heat transfer in the evaporator.
D)
Acts as an insulator reducing the heat transfer of the coil.
Answer:
D
Explanation:
27
107)
107)
Which of the following modifications would alleviate the stress on a compressor in a long–line
system?
A)
Reducing refrigerant charge
B)
Using a hard–shutoff TEV at the evaporator
C)
Removing any compressor crankcase heaters
D)
Adding a compressor hard–start kit
Answer:
D
Explanation:
108)
108)
Which of the following statements is TRUE about double risers within suction lines?
A)
During part–load operation, refrigerant is forced through the larger riser.
B)
During full–load operation, refrigerant is forced through the larger riser.
C)
During full–load operation, refrigerant is forced through the smaller riser.
D)
During part–load operation, refrigerant is forced through the smaller riser.
Answer:
D
Explanation:
109)
109)
A system using R–404a has an evaporation temperature of 0°F. If the line length is 100 ft and the
system needs a capacity of 2 tons, what size line should be used?
A)
5/8 in
B)
3/4 in
C)
1–1/8 in
D)
7/8 in
Answer:
D
Explanation:
110)
110)
The maximum pressure drop for a suction line should not exceed:
A)
2 psi.
B)
1 psi.
C)
3 psi.
D)
A corresponding saturation temperature drop of 2°F.
Answer:
D
Explanation:
28
111)
111)
Oversized suction lines:
A)
Can cause poor oil return because of low refrigerant velocity.
B)
Can reduce system efficiency because of a low pressure drop.
C)
Can cause poor oil return because of high refrigerant velocity.
D)
Can reduce system efficiency because of a high pressure drop.
Answer:
A
Explanation:
112)
112)
An R–22 system has a 28–ft lift and a 7 psi pressure drop in the liquid line due to vertical lift. If the
liquid leaves the condenser at 244 psi, what is the pressure at the top of the vertical lift?
A)
230 psi
B)
223 psi
C)
214 psi
D)
237 psi
Answer:
B
Explanation:
113)
113)
Refrigerant piping must be able to adequately carry both refrigerant and:
A)
Air.
B)
Nitrogen.
C)
Oil.
D)
Electricity.
Answer:
C
Explanation:
114)
114)
In a parallel compressor system, oil often does not return at the same rate to all of the compressors
because:
A)
Only some of the compressors require oil return.
B)
All the compressors do not operate for the same length of time.
C)
Parallel compressors are normally stacked vertically, so most of the returning oil returns to
the crankcase of the bottom compressor.
D)
All the compressors do not use the same type of refrigerant oil.
Answer:
B
Explanation:
29
115)
115)
Why are vertical suction risers often smaller than the horizontal runs on the same suction line?
A)
The risers are sized smaller to minimize noise.
B)
The risers are sized smaller to increase the pressure drop for improved control.
C)
The risers are sized smaller to maintain a minimum velocity to lift the oil.
D)
The risers are sized smaller to minimize pressure drop.
Answer:
C
Explanation:
116)
116)
A system using R–404a has an evaporation temperature of 20°F. If the line length is 100 ft and a
7/8 in line is used, what is the maximum capacity of the system?
A)
2 tons
B)
2.5 tons
C)
1.5 tons
D)
3 tons
Answer:
A
Explanation:
117)
117)
Which pair of factors most directly affects the maximum allowable pressure drop within a
system?
A)
Temperature of refrigerant and type of refrigerant
B)
Type of refrigerant and pipe size
C)
Type of refrigerant and gas velocity
D)
Temperature of refrigerant and gas velocity
Answer:
A
Explanation:
118)
118)
For most systems, the minimum velocity in a horizontal suction line is:
A)
1,0001,500 ft per minute.
B)
7501,000 ft per minute.
C)
3,0003,500 ft per minute.
D)
500750 ft per minute.
Answer:
D
Explanation:
30
119)
119)
Flash gas in the liquid line can be identified by:
A)
The popping sound the refrigerant makes every time a new flash explodes.
B)
A significant temperature drop in the liquid line temperature.
C)
The bright flashes of light that accompany the flash gas.
D)
A significant temperature increase in the liquid line temperature.
Answer:
B
Explanation:
120)
120)
Which of the following statements is TRUE about these systems?
A)
The R410a system can operate at half the suction line pressure drop of the R–22 system.
B)
The R–410a system can operate at twice the suction line pressure drop of the R–134 system.
C)
The R–22 system can operate at twice the suction line pressure drop of the R–410a system.
D)
The R–22 system can operate at the same suction line pressure drop of the R–410a system.
Answer:
B
Explanation:
121)
121)
The pressure drop for R–22 due to vertical lift ina liquid line is approximately:
A)
0.2 psi per foot of lift.
B)
0.5 psi per foot of lift.
C)
2 psi per foot of lift.
D)
1 psi per foot of lift.
Answer:
B
Explanation:
122)
122)
Modifications such as adding a liquid–line solenoid at the outdoor unit, using a hard shutoff
thermal expansion valve at the evaporator, and adding a compressor hard–start kit are
recommended when:
A)
The refrigerant line length is less than 50 ft.
B)
The refrigerant line length is over 80 ft.
C)
The system is converted from 22 to 410a.
D)
The refrigerant line length is over 40 ft.
Answer:
B
Explanation:
31
123)
123)
When installing a double riser in a commercial refrigeration system, which of the following
statements is TRUE?
A)
The combined areas of the risers should be greater than the area of the suction line.
B)
The combined areas of the risers should be less than the area of the suction line.
C)
The combined areas of the risers should be equal to the area of the suction line.
D)
Both of the risers should be the same size.
Answer:
C
Explanation:
124)
124)
The hot gas lines need to be insulated:
A)
Never.
B)
Always.
C)
For systems using HFC refrigerants.
D)
If they are exposed to cold temperatures that could cause the refrigerant to condense in the
line.
Answer:
D
Explanation:
125)
125)
Which of the following modifications would alleviate refrigerant migration in a long–line system?
A)
Reducing refrigerant charge
B)
Adding a liquid line solenoid
C)
Removing any compressor crankcase heaters
D)
Adding a compressor hard–start kit
Answer:
B
Explanation:
126)
126)
For most systems, the minimum velocity in a vertical suction line is:
A)
1,0001,500 ft per minute.
B)
3,0003,500 ft per minute.
C)
500750 ft per minute.
D)
7501,000 ft per minute.
Answer:
A
Explanation:
32
127)
127)
Besides improving efficiency, insulating the suction line:
A)
Reduces mechanical vibrations set up by the compressor.
B)
Serves as a backup sealing system to prevent refrigerant loss.
C)
Prevents moisture from condensing on the line.
D)
Prevents stray electrical current from traveling down the pipe.
Answer:
C
Explanation:
128)
128)
The refrigerant line whose sizing has the most effect on the compressor’s compression ratio is the:
A)
Suction line.
B)
Discharge line.
C)
Liquid line.
D)
Refrigerant line sizing has no effect on compression ratio.
Answer:
A
Explanation:
129)
129)
What personal protective equipment (PPE) should be worn when using manifold gauges?
A)
Safety glasses
B)
Safety glasses and gloves
C)
No PPE is required if you are careful.
D)
Gloves
Answer:
B
Explanation:
130)
130)
After servicing a system using a bolt–on piercing valve, the technician should:
A)
Close the bolt–on valve, remove the gauges, and put on the valve cap.
B)
Simply remove the gauges because most bolt–on valves are self–sealing.
C)
Remove the bolt–on valve and quickly braze up the hole.
D)
Recover the refrigerant, remove the bolt–on valve, and replace it with a permanent valve.
Answer:
D
Explanation:
33
131)
131)
Why do some technicians recommend using a separate refrigerant tank when purging hoses?
A)
To preserve coolant
B)
To maintain pressure levels
C)
To preserve system charge
D)
To continue refrigerant flow
Answer:
C
Explanation:
132)
132)
What is the problem associated with discharging a gauge manifold through its middle leg?
A)
There is a need to replace the hose.
B)
There is wearing on the valves.
C)
There is a loss of refrigerant.
D)
There is the use of extra power to the unit.
Answer:
C
Explanation:
133)
133)
When connecting gauges to an already installed and operating unit with split–system installation
valves, the installation valves should be:
A)
Left alone.
B)
Moved to the mid position to allow the gauges to read the system pressures.
C)
Backseated as tightly as possible to prevent refrigerant from escaping.
D)
Frontseated to allow the gauges to read the system pressures.
Answer:
A
Explanation:
134)
134)
When connecting a gauge manifold set, the air inside the hoses and gauge manifold:
A)
Is negligible and will not adversely affect the system.
B)
Is removed by purging.
C)
Is removed by connecting a vacuum pump to the gauges before connecting them.
D)
Is neutralized by adding chemical buffers to the system annually.
Answer:
B
Explanation:
34
135)
135)
When a manual service valve is backseat cracked:
A)
The service port is closed and the system is open to the line.
B)
Both the service port and the line are closed to the system.
C)
The service port is open and the system is closed to the line.
D)
Both the service port and the line are open to the system.
Answer:
D
Explanation:
136)
136)
Split–system heat pumps have a third service valve that is not connected to either refrigerant line.
This extra valve:
A)
Is only needed during the cooling cycle.
B)
Is used to read the defrost pressures during the defrost cycle.
C)
Is a backup in case one of the other service valves quits functioning.
D)
Is always connected to the low side of the system regardless of the operating cycle.
Answer:
D
Explanation:
137)
137)
What type of units are only required to have process stubs?
A)
Type I only
B)
Type II only
C)
All systems are required to have process stubs.
D)
Type II and Type III
Answer:
A
Explanation:
138)
138)
What types of system access valves do residential air–conditioning 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:
C
Explanation:
35
139)
139)
A saddle piercing valve:
A)
Is used to pierce the saddle on a manual service valve whose stem has been rounded off so
the technician can still get a reading.
B)
Is used to gain access to a sealed system.
C)
Should be installed on all systems at the start of a service call.
D)
Is the most common type of refrigeration service valve used on commercial refrigeration
systems.
Answer:
B
Explanation:
140)
140)
When should gauges be installed on small sealed systems?
A)
Routinely, at least every year
B)
Only when other diagnostic means have been exhausted
C)
Whenever the system is checked
D)
Monthly to ensure the charge is still correct
Answer:
B
Explanation:
141)
141)
When can a compound gauge can be connected to a pressure higher than the maximum pressure
it can read accurately?
A)
Only if the hose ends are reversed to prevent overpressurizing the gauges
B)
Only if the pressure does not exceed its retard range
C)
Anytime. It does not hurt a gauge to be connected to pressures above its rating.
D)
Never. Gauges should never be connected to pressures above the maximum pressure that
the gauge can accurately read.
Answer:
B
Explanation:
36
142)
142)
If a technician needs to read the refrigerant pressure of a window unit, they must:
A)
Use a hose that has a depressor core for the Schrader valve.
B)
Use a piercing valve.
C)
First cut open the process stub on the compressor.
D)
Backseat crack the compressor access valve.
Answer:
B
Explanation:
143)
143)
One way to reduce the amount of refrigerant spray when connecting and disconnecting
refrigeration hoses from Schrader valves is to:
A)
Use positive shutoff hoses.
B)
Make sure the system is operating before connecting or disconnecting from the high side.
C)
Loosen the end of the hose on the gauge manifold and slowly release the pressure.
D)
Pinch the hose closed behind the fitting with a pair of pliers before removing the hose.
Answer:
A
Explanation:
144)
144)
Why is it most important to take special precautions when working with Schrader valves?
A)
They are most easily broken during the process of tightening.
B)
Their opening leads to the release of a large amount of refrigerant.
C)
The type of refrigerant that passes through them is exceptionally toxic.
D)
They can cause irreparable system damage if improperly used.
Answer:
B
Explanation:
145)
145)
Most type I systems are evacuated and charged at the factory through:
A)
The king valve.
B)
Both the suction service and king valves.
C)
A process tube or process stub.
D)
The suction service valve.
Answer:
C
Explanation:
37
146)
146)
Why are piercing valves used in refrigerant work?
A)
To access a sealed system
B)
To allow a constant evacuation
C)
To install a gauge manifold set
D)
To remove a process tube
Answer:
A
Explanation:
147)
147)
What type of units are required by the EPA to have service valves?
A)
Type II only
B)
Types I, II, and III
C)
Type II and Type III
D)
Type I only
Answer:
C
Explanation:
148)
148)
Slightly opening a valve is called:
A)
Breaking the valve.
B)
Testing the valve.
C)
Cracking the valve.
D)
Hedging the valve.
Answer:
C
Explanation:
149)
149)
When a manual service valve is backseated:
A)
The service port is open and the system is closed to the line.
B)
The service port is closed and the system is open to the line.
C)
Both the service port and the line are closed to the system.
D)
Both the service port and the line are open to the system.
Answer:
B
Explanation:
38
150)
150)
Why are split–system installation valves typically NOT used following installation?
A)
They do not control flow to service ports.
B)
They are usually stuck in the closed position.
C)
They are usually stuck in the open position.
D)
They limit flow to the service ports.
Answer:
A
Explanation:
151)
151)
How do the three position service valves differ from other valves?
A)
They have no closed position.
B)
They are leakproof, if undamaged.
C)
They are spring–loaded.
D)
They have multiple closed positions.
Answer:
A
Explanation:
152)
152)
What is the purpose of a gauge manifold valve?
A)
To limit the flow of refrigerant to the outside of the valve
B)
To control refrigerant flow to the gauge’s center
C)
To allow for a permanent opening for refrigerant flow
D)
To cut off refrigerant flow from the center of the gauge
Answer:
B
Explanation:
153)
153)
Why is backseating a manual service valve when installing a gauge manifold necessary?
A)
So that the middle leg is opened
B)
So that there is no pressure on the gauge port
C)
So that no gauge ports are opened
D)
So that coolant is not lost
Answer:
B
Explanation:
39
154)
154)
To speed up refrigerant recovery:
A)
Recover from only one side of the system at a time.
B)
Use small–diameter, long–length hoses.
C)
Keep the system as cool as possible.
D)
Use large–diameter, short–length hoses.
Answer:
D
Explanation:
155)
155)
How does reclaimed refrigerant differ from recovered or recycled refrigerants?
A)
Reclaimed refrigerants cannot be reused.
B)
Reclaimed refrigerants can be reused.
C)
Reclaimed refrigerants cannot be put back into the same system.
D)
Reclaimed refrigerants can be put into new systems.
Answer:
D
Explanation:
156)
156)
What is the maximum safe fill weight of a recovery cylinder with a tare weight of 30 lb, a water
capacity of 40 lb, holding a refrigerant with a specific gravity of 1.2?
A)
(30 lb + 40 lb) × 1.2 = 84 lb (rounded)
B)
30 lb + (40 lb × 0.8 × 1.2) = 68 lb (rounded)
C)
30 lb + 40 lb = 70 lb (rounded)
D)
(30 lb + 40 lb) × 0.8 = 56 lb (rounded)
Answer:
B
Explanation:
157)
157)
What is the maximum safe amount of refrigerant for a recovery cylinder with a water capacity of
50 lb, holding a refrigerant with a specific gravity of 0.9?
A)
50 lb × 0.9 = 45 lb
B)
50 lb
C)
50 lb × 0.8 × 0.9 = 36 lb
D)
50 lb × 0.8 = 40 lb
Answer:
C
Explanation:
40