ACHR230 FINAL REVIEW
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ACHR230 Final Review. Multiple Choice, T/F, & Fill-in the blank.
- 1.When moisture is present in a refrigeration system, it will react with the refrigerant and the oil to form ________.
- A.
Carbon dioxide
- B.
Acid
- C.
Carbon monoxide
- D.
All of the above
- 2.Which of the following represents the lowest vacuum?
- A.
10 psia
- B.
5" Hg VAC
- C.
5 psig
- D.
1000 microns
- 3.
- A.
Raise the pressure in a refrigeration system
- B.
Lower the pressure in a refrigeration system below atmospheric
- C.
Allow refrigerant to escape into the atmosphere
- D.
Condense the gas in the system
- 4.A compound gauge ________.
- A.
Indicates pressures above 14.696 psia
- B.
Indicates pressures in inches Hg below atmospheric pressure
- C.
Is one of two gauges on a typical gauge manifold
- D.
All of the above
- 5.A micron gauge is used to measure
- A.
Atmospheric pressures at high altitudes
- B.
Atmospheric pressures at sea level
- C.
Absolute pressures below 1 mm Hg
- D.
High pressure in a refrigeration system
- 6.The best method of leak checking is when the refrigeration system is ________.
- A.
In a vacuum
- B.
Open to the atmosphere
- C.
Operation with all fans activated
- D.
Standing with dry nitrogen pressure of 150 psig in the system
- 7.Noncondensable gases ________.
- A.
Are desirable in a refrigeration system
- B.
Are undesirable in a refrigeration system
- C.
Condense readily under normal atmospheric conditions
- D.
Help in pulling a vacuum
- 8.What is the most accurate instrument for checking a deep vacuum?
- A.
Compound gauge
- B.
Mercury "U" tube manometer
- C.
Mercury barometer
- D.
Electronic vacuum gauge
- 9.To insure accurate testing, the best material to use for connecting lines to the vacuum pump and gauge set is ________.
- A.
Light flexible hose
- B.
Heavy duty rubber gauge line
- C.
Copper tube
- D.
Garden hose
- 10.A multiple evacuation means that ________.
- A.
You connect three vacuum pumps simultaneously to a refrigeration system and pull a vacuum
- B.
You pull a vacuum on three different systems at the same time
- C.
You pull a vacuum on a refrigeration system more than once, allowing refrigerant or nitrogen into the system between each procedure
- D.
There must be more than one system operating before a vacuum can be pulled
- 11.Moisture in a liquid state must be ________ before it can be removed with a vacuum pump.
- A.
Vaporized
- B.
Condensed
- C.
Cooled
- D.
Solidified
- 12.How many chlorine atoms does it take to destroy 100,000 ozone molecules in the stratosphere?
- A.
10
- B.
1
- C.
100
- D.
10,000
- 13.Which of the following refrigerants is a CFC-type refrigerant?
- A.
R-22
- B.
R-123
- C.
R-134a
- D.
R-12
- 14.Which of the following is an example of an HCFC refrigerant?
- A.
R-12
- B.
R-402
- C.
R-22
- D.
R-134a
- 15.Which of the following refrigerants is considered an HFC-type of refrigerant?
- A.
R-134a
- B.
R-12
- C.
R-22
- D.
R-11
- 16.Which type of refrigerant has the highest Ozone Depletion Potential (ODP)?
- A.
HFC
- B.
HCFC
- C.
CFC
- D.
All have the same ODP.
- 17.What effect is ozone depletion having on the environment?
- A.
Increased ground level ozone (smog)
- B.
Reduced marine life
- C.
Reduced crop fields
- D.
All of the above
- 18.The abbreviation for refrigerants containing chlorine, fluorine, and carbon is ________.
- A.
HFC
- B.
HCFC
- C.
CFC
- D.
HFAC
- 19.The abbreviation for refrigerants containing chlorine, fluorine, carbon, and hydrogen is ________.
- A.
HFC
- B.
HCFC
- C.
CFC
- D.
HFAC
- 20.The abbreviation for refrigerants containing fluorine, carbon, and hydrogen is ________.
- A.
HFC
- B.
HCFC
- C.
CFC
- D.
HFAC
- 21.To reprocess refrigerant to meet new product specifications is called ________.
- A.
Recovery
- B.
Renew
- C.
Reclaim
- D.
Recycle
- 22.
![]()
To clean refrigerant by the use of filter dryers is called- A.
Recovery
- B.
Renew
- C.
Reclaim
- D.
Recycle
- 23.To remove the refrigerant from a system without any testing or processing and to be put back into the same system is called ________.
- A.
Recovery
- B.
Renew
- C.
Reclaim
- D.
Recycle
- 24.Refrigerants that are made up of two refrigerants that, when blended in the right proportions, combine to make a third stable refrigerant, are called ________.
- A.
Blends
- B.
Azeotropes
- C.
Near azeotropes
- D.
Mixtures
- 25.The ozone depletion factor of R-12 is ________.
- A.
0.8
- B.
0.016
- C.
0.05
- D.
1.0
- 26.If a critically charged refrigeration system is over charged, which of the following is a likely result?
- A.
Increased cooling capacity
- B.
Reduced compressor discharge temperature
- C.
Increased system efficiency
- D.
Increased operating pressures
- 27.Fractionation occurs when ________.
- A.
Some of a blended refrigerant evaporates or condenses before the rest of the blend
- B.
When only a fraction of the total charge has been added to a system
- C.
The operating pressures of a system increase
- D.
Both a and c
- 28.When charging a refrigeration system with a near-azeotropic mixture, what must be done to prevent liquid from entering the system?
- A.
Charge only as a vapor through the high side.
- B.
Charge only liquid through the high side.
- C.
Charge as a liquid through the low side using a restrictor.
- D.
Charge as a vapor through the low side using a resistor.
- 29.Charging a refrigeration system refers to ________.
- A.
Removing refrigerant from a system
- B.
Adding refrigerant to a system
- C.
Cleaning the refrigerant
- D.
Vaporizing the refrigerant
- 30.
- A.
22 lb. 12 oz.
- B.
22 lb. 6 oz.
- C.
22 lb. 8 oz.
- D.
23 lb. 6 oz
- 31.If 30 oz. of refrigerants are to be added to a refrigeration system and the supply cylinder weighs 26 lb. 4 oz. before any is added, what will the supply cylinder weigh after the system has been charged?
- A.
22 lb. 8 oz.
- B.
24 lb. 6 oz.
- C.
24 lb. 8 oz.
- D.
22 lb. 4 oz.
- 32.Refrigerant in liquid form is normally put into a system through the ________.
- A.
Liquid line
- B.
Suction line
- C.
Hot gas line
- D.
Liquid return line
- 33.Refrigerant in vapor from is normally put into the system through the ________.
- A.
Liquid line
- B.
Suction line
- C.
Hot gas line
- D.
Liquid return line
- 34.When charging a system with vapor refrigerant from a refrigerant cylinder the cylinder will become ________.
- A.
Cold
- B.
Very warm
- C.
The same temperature as the ambient air
- 35.When charging liquid refrigerant from a single valve supply cylinder, the cylinder is placed ________.
- A.
Upside down
- B.
Right side up
- C.
On its side
- D.
In any position indicated
- 36.A graduated cylinder charging device is a device that ________.
- A.
Measure refrigerant by volume for precise refrigerant charging
- B.
Has a compensation dial for adjusting for the temperature of the refrigerant
- C.
Often has a heater to keep the refrigerant temperature from dropping when refrigerant is released into the system
- D.
All of the above
- 37.
- A.
6 lb. 10 oz.
- B.
6 lb. 15 oz.
- C.
7 lb. 7 oz.
- D.
7 lb. 11 oz.
- 38.After repairing a system that has had an electrical motor failure (compressor burnout), it is a good field practice to re-use the recovered refrigerant in that system.
- A.
True
- B.
False
- 39.Air entering a refrigerant system can eventually lead to compressor failure.
- A.
True
- B.
False
- 40.Clearance tolerances are such that the ordinary clean refrigerant oil can be used satisfactorily in a vacuum pump.
- A.
True
- B.
False
- 41.While under a deep vacuum, any liquid water under the oil in the motor-compressor assembly can be removed by operating the compressor motor for several seconds without any adverse effect on the system.
- A.
True
- B.
False
- 42.The maximum recommended pressure for leak testing is 150 psig.
- A.
True
- B.
False
- 43.The oil in a vacuum pump should be changed after each time it is used.
- A.
True
- B.
False
- 44.It is possible to have a leak-free system when under a vacuum but still leak when the system pressure is above atmospheric.
- A.
True
- B.
False
- 45.Refrigerants that have a low Ozone Depletion Potential (ODP) will, in turn, have a high "Total Equivalent Warming Impact" (TEWI).
- A.
True
- B.
False
- 46.The DOT-approved cylinder used for recovering refrigerant is gray and yellow.
- A.
True
- B.
False
- 47.A refrigerant reclaimed from a system may be charged back into the system from which it came.
- A.
True
- B.
False
- 48.Mechanical refrigerant recovery equipment must meet specification established by the 1993 ARI 740 standard.
- A.
True
- B.
Flase
- 49.When technicians works for a company in which the technician does not have a financial interest, the technician does not have to be certified.
- A.
True
- B.
False
- 50.Glide is the range of temperatures/pressures in which a blended refrigerant will condense.
- A.
True
- B.
False
- 51.One good feature of an electronic charging scale is that it counts upward as refrigerant is removed, to tell the the technician how much refrigerant was used.
- A.
True
- B.
False
- 52.The quickest method to charge a system is to charge only vapor.
- A.
True
- B.
False
- 53.When adding refrigerant in vapor form to a refrigeration system, the system motor/compressor assembly is running.
- A.
True
- B.
False
- 54.When adding refrigerant in liquid form into the high-side of the system, the system motor/compressor assembly is running.
- A.
True
- B.
False
- 55.Using a restrictor, liquid refrigerant can be charged into the low-side of the system with the system operating.
- A.
True
- B.
False
- 56.A manufacturer's charging chart may be used when available to determine the correct charge for a system.
- A.
True
- B.
False
- 57.When the system pressures are lower than the pressure in the refrigerant tank, such as when the system has just been evacuated or if the system is out of refrigerant, refrigerant can be added to both the high and low pressure sides of the system.
- A.
True
- B.
False
- 58.If the tank is a reusable tank, there are no check valves and system refrigerant can enter the tank as long as the system pressure is higher than the pressure in the tank.
- A.
True
- B.
False
- 59.When using a "standing pressure test" for leak-checking, ________ should never be used since an explosive mixture can be created.
- 60.________ microns is equal to 1 mm Hg.
- 61.The temperature sensitive resistor commonly used in a vacuum gauges is called a ________.
- 62.Sludge is a produced when ________, ________, and ________ are present in the system.
- 63.There are ________ microns in 1 mm Hg.
- 64.Only two substances should be in the refrigeration system for proper operation. They are ________ and ________.
- 65.A deep vacuum involves reducing the pressure in a refrigeration system to a micron gauge reading of ________ or below.
- 66.The sensing element of a micron gauge must always be mounted with the fitting at the ________.
- 67.Ozone is produced mainly by a process called ________ .
- 68.The trapping of the Earth's heat in the atmosphere which is causing global warming is called the ________.
- 69.HCFC-based blends work best with ________ lubricants, while HFC-based blends work best with ________ lubricants.
- 70.Production of CFC refrigerants became illegal on ________.
- 71.Refrigerants that damage the ozone layer contain an element called ________.
- 72.The DOT-approved cylinder in which refrigerant may be recovered has a mechanism for shutting the recovery system off when it reaches approximately ________ full.
- 73.The fastest way to remove refrigerant from a system is with the refrigerant in a ________.
- 74.The fine for venting refrigerant into the atmosphere can be as high as ________ per day.
- 75.When working on a refrigeration or air-conditioning system, along with tools and test equipment, the service technician, to avoid penalty, must have a ________ or ________ on the job site.
- 76.The small amount of refrigerant released when removing gauge hoses from the system is called ________.
- 77.The charging device that holds refrigerant, has a visible column of liquid, and can be used to "visually" see the amount of refrigerant used is called the ________.
- 78.Refrigerant in vapor form is added to the system through the ________ side of the system.
- 79.When refrigerant cylinder is connected to an operating system, the pressure in the cylinder will be ________ than the suction pressure of the system.
- 80.As refrigerant vapor is removed from a supply cylinder, the pressure in the supply cylinder will ________.
- 81.The ________ is used to help technicians perform a number of tasks including taking pressure readings on the high side of the system and trapping all of the system refrigerant in the receiver to perform system service.
- 82.A device commonly used for detecting refrigerant leaks is a(n) ________.
- A.
Electronic leak detector
- B.
Halide torch
- C.
Soap bubbles
- D.
All of the above
- 83.When taking a temperature reading of a copper suction line, it is important to insulate the sensing element to give a more accurate reading.
- A.
True
- B.
False
- 84.The accuracy of a thermometer is more important when working on high temperature refrigeration (air conditioning) systems.
- A.
True
- B.
False
- 85.When taking the temperature of the liquid line of a refrigeration system, the thermometer probe of an electronic thermometer does not have to be insulated.
- A.
True
- B.
False
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