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Mod B Section 1 Mid Term Flashcards | StudBud
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Mod B Section 1 Mid Term
Mod B Section 1 Mid Term
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Midterm for Mod B section 1
Flashcards
90 cards
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Practice quiz
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Questions
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Answers
1
is used most frequently for amperage checks
integrated ammeter
alternating ammeter
hot-wire ammeter
clamp-on ammeter
2
The compressor in a refrigeration system
pumps the refrigerant throughout the system
None of the above
lowers the boiling point of the refrigerant
Both a and b
3
Non-condensable gases
All the above
condense readily under normal atmospheric conditions
are desirable in a refrigeration system
are undesirable in a refrigeration system
4
What is the purpose of a receiver
It is required on all fixed-metering device systems
Used to legally vent refrigerant
To prevent refrigerant from flooding the compressor
It is used as a refrigerant storage tank
5
The condenser
adds superheat to the refrigerant
rejects the heat from the refrigerant
controls the refrigerant flow throughout the system
All of the above
6
A compound gauge
is one of two gauges on a typical gauge manifold
indicates pressures above 14.696 psia
indicates pressures in inches Hg below atmospheric pressure
All of the above
7
Vapor is denser than liquid and, as the liquid refrigerant boils, it has a tendency to sink.
False
True
8
Clean refrigerant by the use of filter dryers to be reused in the same unit or one owned by the same person/owner is
reclaim
recycle
recovery
renew
9
what color code is used by R-404 refrigerant
light blue
orange
purple
pink
10
important to note that Ohms law will hold for AC-powered circuits that are used to operate resistive-type loads
True
False
11
Cylinder of R-22 is moved from 100°F truck body to 80°F shop, amount of liquid refrigerant in the tank will be the same
True
False
12
The evaporator absorbs heat
True
False
13
When moisture is present in a refrigeration system, it will react with the refrigerant and the oil to form
carbon monoxide
carbolic acid
carbon dioxide
acid
14
When a refrigerant enters the compressor, it is a ____ and when it leaves the compressor, it is a ____
low press,low temp,superheated vapor, hi press hi temp superheated vapor
low press low temp superheated vapor, low press low temp subcooled vapor
low press low temp subcooled liquid, high press high temp superheated vapor
high pressure superheated vapor; low pressure superheated vapor
15
The law requires technicians to recover refrigerant from all refrigeration systems so that they
may be used again
will not be released into the atmosphere
All of the above
may be reclaimed for future use
16
A multiple evacuation means that
you pull a vacuum on three different systems at the same time
Pull a vacuum on refrig system more than once, allow N2 between each break
there must be more than one system operating before a vacuum can be pulled
you connect three vacuum pumps to a refrigeration system and pull a vacuum
17
The evaporator in a refrigeration system
condenses the refrigerant
reduces the boiling point of the refrigerant
absorbs heat from the product to be cooled
compresses the refrigerant vapor
18
What type of system would most likely use an accumulator
Dehumidifiers
Medium temperature walk-ins with multiple evaporators
Heat pumps and commercial freezers
Air conditioning systems over 10 tons
19
Which of the following refrigerants is a CFC-type refrigerant
R-123
R-12
R-134a
R-22.
20
Which of the following is an example of an HCFC refrigerant
R-134a
R-12
R-32
R-22
21
Read Picture
False
True
22
Three reference points for checking temperature measuring instruments are
32°F, 100°F, 250°F
-460°F, 0°F, 32°F
0°F, 100°F, 110°F
32°F, 98.6°F, 212°F
23
Flue-gas analysis instruments analyze products of combustion from fossil-fuel–burning equipment, like oil,gas furnaces,
cooling towers
boilers
refrigerators
CO2 testers
24
For a system in normal running operation, the king valve must be
mid-seated
back seated
front seated
mid cracked seated
25
A ton of refrigeration is equal to
1 ton of crushed ice
12,000 Btu/hour
288,000 Btu/hour
144 Btu/min
26
Which type of refrigerant has the highest Ozone Depletion Potential
All have same ODP
HCFC
HFC
CFC
27
The abbreviation for refrigerants containing fluorine, carbon, and hydrogen is
CFC
HFAC
HCFC
HFC
28
If there are bubbles in the sight glass, the technician must alwaysadd refrigerant to the system
False
True
29
Moisture in a liquid state must be ____ before it can be removed with a vacuum pump
condensed
none of the above
cooled
solidified
30
To pump down a system, the king valve must be
back seated
Front seated
mid cracked seated
mid-seated
31
The temperature inside the refrigerator fresh food section should be about
25ºF
45ºF
35ºF
55ºF
32
A device commonly used for detecting refrigerant leaks is a(n)
compressed air canister
water pump
None of the above
oxide torch
33
To check the temperature leads of a electronic thermometer for low temperature, they should be stirred in a container of
crushed ice and water with 1/2 teaspoon of sugar added
crushed ice and pure water
crushed ice and water with 1/2 teaspoon of salt added
cube ice and pure water
34
What is the purpose of vibration absorbers
emit vibrations to aid refrigerant vaporization
dampen the noise put out by semi-hermetic compressors
prevent hermetic compressor vibration from damaging the compressor
prevent semi-hermetic compressor vibration from damaging piping
35
Refrigeration can be described as
none of above
removing heat from a place where it is not wanted to a place, makes no diff
the process of introducing heat to a location where it is not wanted
the process of making products cold
36
Accuracy of a thermometer is more important when working on high temperature refrigeration (air conditioning) systems
False
True
37
The Condenser Absorbs heat as liquid refrigerant boils
False
True
38
Water boils at 100°F at sea level under standard atmospheric conditions
False
True
39
Suction line filter driers work best when installed on the suction line
True
False
40
What is the primary purpose of a heat exchanger
to super heat liquid to prevent condensation
To boil off liquid refrigerant before it gets to the compressor
To sub-cool liquid to prevent flashing before entering the metering device
To maintain refrigerant in a liquid state as it leaves the condenser
41
The abbreviation for refrigerants containing chlorine, fluorine, carbon, and hydrogen is
CFC
HFC
HFAC
HCFC
42
Which of the following represents the lowest vacuum
1000 microns
5 in. Hg vacuum
5 psig
10 psia
43
If the ammeter is off by more than _____%, it should be sent to the repair shop or replaced
50
None of the above
20
70
44
what color code is used by R-410a refrigerant
orange
purple
lime green
pink
45
How many chlorine atoms does it take to destroy 100,000 ozone molecules in the stratosphere
100
1,000,000
10
1
46
Where is the accumulator located
Suction Line
Vapor Line
Discharge line
Liquid Line
47
The B.P of refrigerant should be low enough at atmo press to keep the SYS press above 0 psig when operating at low temp
False
True
48
The oil in a vacuum pump should be changed after each time it is used
False
True
49
The best method of leak checking is when the refrigeration system is
standing with dry nitrogen pressure of 150 psig in the system
operating with all fans activated
open to the atmosphere
in a vacuum
50
Only liquid refrigerant should enter the metering device
False
True
51
Moisture in a liquid state must be ____ before it can be removed with a vacuum pump
vaporized
emulsified
condensed
solidified
52
At what pressure range does the technician valve off the vacuum pump when evacuating to a deep vacuum
300 to 100 microns
300 to 200 microns
500 to 300 microns
200 to 100 microns
53
There should be only two substances should be in the refrigeration system for proper operation. They are
mud & ice
steam & sludge
refrigerant & oil
water & oil
54
Relationship correlates the vapor press and the B.P of water and is the basis for controlling the cooling system’s temp.
temperature/pressure
boiling/pressure
boiling/vapor
temperature/vapor
55
Clearance tolerances are such that the ordinary clean refrigerant oil can be used satisfactorily in a vacuum pump.
True
False
56
The maximum recommended pressure for leak testing is 150 psig on the low-pressure side of the system.
True
False
57
To process refrigerant to new product specifications is called
renew
recycle
reclaim
recovery
58
If there are bubbles in the sight glass, the technician must always add refrigerant to the system
False
True
59
what color code is used by R-22 refrigerant
green
pink
purple
white
60
Reciprocating compressors have
a rotor to compress the refrigerant
a piston and cylinder
a large fan compressor component
two scrolls that mesh together
61
Mechanical refrigerant recovery equipment must meet specifications established by the 1993 ASHRI 740 standard
True
False
62
While in vacuum any liquid water under the oil compressor assembly can b removed by operating the compressor without dmg
False
True
63
To remove the refrigerant from a system without any testing or processing and to put into an approved cylinder
renew
recycle
recovery
reclaim
64
What type of system requires an oil separator
Any system that was made before 1991
Any system that has very long piping runs
Any system that trips the oil safety control
Any system that has oil return problems
65
Modern refrigerators have become state of the art and some even include auto beverage and ice dispensers, built in tv
True
False
66
One recommendation to prevent suction line filters from becoming a source of excessive pressure drop?
They should not be left in the system
Only use on systems over 12,000 Btu/h capacity
They should not be used for moisture removal
They should only be used for burnouts
67
Which of the following refrigerants is considered an HFC-type of refrigerant
R-11
R-134a
R-22
R-12
68
can detect leak rates of about 1/4 oz per year
Compressed air canisters
Mechanical leak detectors
Halide torches
Electronic leak detectors
69
To pull a vacuum means to
raise the pressure in a refrigeration system
allow refrigerant to escape into the atmosphere
lower the pressure in a refrigeration system below atmospheric
condense the gas in the system
70
What part of a filter dryer removes dirt and acids
Fiberglass pads
The screen and strainer
All parts of the filter drier
The desiccant
71
The primary purpose of crankcase heaters is to keep refrigerant from migrating under the oil
False
True
72
To insure accurate testing, the best material to use for connecting lines to the vacuum pump and gauge set is
light flexible hose
copper tube
garden hose
heavy duty rubber gauge line
73
The discharge gas from the compressor is a high pressure, high temperature, superheated vapor
False
True
74
are used to change the vapor to a liquid and the liquid form back into a vapor, the refrigeration cycle
condenser and evaporator
expansion device and evaporator
compressor and expansion device
condenser and compressor
75
After repairing a system that had compressor burnout it is good field practice to re-use the recovered refrigerant
False
True
76
Refrigerants that have a low Ozone Depletion Potential (ODP) will have a high "Total Equivalent Warming Impact" (TEWI
False
True
77
What is the purpose of an accumulator
For storing refrigerant vapor in the suction line
It is required on all systems
To prevent liquid from flooding the compressor
For storing liquid refrigerant in the liquid line
78
Receivers are located in which line?
Suction Line
Liquid Line
Vacuum Line
Discharge Line
79
Good ventilation is important when working around refrigeration equipment because modern refrigerants
are toxic and can poison you
Both a and c
have an unpleasant odor
are heavier than air and may displace the oxygen around you
80
A refrigerant recovered from a system may be charged into any other system
False
True
81
The abbreviation for refrigerants containing chlorine, fluorine, and carbon is
HCFC
HFC
HFAC
CFC
82
Air entering a refrigerant system can eventually lead to compressor failure
True
False
83
The only location where the refrigerant vapor is superheated is in the evaporator
True
False
84
Where is an oil separator located
Suction line
Liquid line
Discharge line
Anywhere there’s enough room
85
A micron gauge is used to measure
atmospheric pressures at sea level
atmospheric pressures at high altitudes
high pressure in a refrigeration system
absolute pressures below 1 mm Hg
86
A tech. works for a company in which the tech doesn't have a financial interest, the tech. does not have to be certified
False
True
87
The DOT-approved cylinder used for recovering refrigerant is gray and red
True
False
88
Some instruments cannot be calibrated
True
False
89
High temperature refrigeration is that produced by
heat from a furnace
an air-conditioning system
the freezer section of a refrigerator
the vegetable cooling system of a refrigerator
90
what color code is used by R-134a refrigerant
light blue
pink
purple
orange
