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Basics Recovery, Evacuation and Charging Flashcards | StudBud
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Basics Recovery, Evacuation and Charging
Basics Recovery, Evacuation and Charging
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Refrigerant Recovery, Leak Check, Evacuation, Refrigerant and Charging Procedures
Flashcards
40 cards
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Practice quiz
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Questions
40
Answers
1
HFC-based blends work best with ____________________ lubricants
PAG
alkylbenzene
POE
mineral oil
2
It is good practice to re-use recovered refrigerant in a unit that has had a compressor burnout
True
False
3
The best method of leak checking is when the refrigeration system is ____.
in a vacuum
operating with all fans activated
standing with dry nitrogen pressure of 150 psig
open to the atmosphere
4
At what pressure does the technician valve off the vacuum pump to meet EPA minimums?
400 microns
300 microns
500 microns
200 microns
5
When charging liquid refrigerant from a single valve cylinder, the cylinder is placed ____.
upside down
right side up
position does not matter
on its side
6
Air entering a refrigerant system can eventually lead to compressor failure.
True
False
7
To remove the refrigerant from a system without any processing and put back into the same unit:
recovery
reclaim
recycle
renew
8
A digital scale will count upward as refrigerant is removed from the system
False
True
9
To reprocess refrigerant to meet new product specifications is called ____.
reclaim
renew
recovery
recycle
10
An overcharged system will display which symptoms?
increased cooling capacity
increased system efficiency
reduced compressor discharge temperature
increased operating pressures
11
Moisture in a liquid state must be ____ before it can be removed with a vacuum pump.
solidified
cooled
condensed
vaporized
12
A compound gauge ____.
indicates above 14.696 psia
all the above
is one of two gauges on a gauge manifold
indicate pressure in inches Hg vacuum
13
The synthetic oil most commonly used with HCFC refrigerants is
Polyoester
Mineral Oil
PolyAlkalineGlycol
Alkybenzene
14
A manufacturer's charging chart may be used if available to determine the correct charge.
True
False
15
To pull a vacuum means to ____.
allow refrigerant to escape into the atmosphere
lower the pressure in a system below atmospheric
raise the pressure in a refrigeration system
condense the gas in the system
16
The quickest method to charge a system is to charge only vapor.
False
True
17
Use the bubble column of a P/T chart when charging a Zeotropic blend for Superheat
True
False
18
low side pressure converted to sat. temp and temp. of the vapor line difference
Superheat
Subcool
19
A micron gauge is used to measure ____.
absolute pressures below 1 mm Hg
atmospheric pressures at high altitudes
atmospheric pressures at sea level
high pressure in a refrigeration system
20
Liquid refrigerant can be added through the high side when the system is in a vacuum.
True
False
21
Clearance tolerances are such that the ordinary refrigerant oil can be used in a vacuum pump.
False
True
22
The additional absorption of heat after the change in state in the evaporator is called
Superheat
Subcool
23
Which of the following represents the lowest vacuum?
5 psig
1000 microns
5" Hg VAC
10 psia
24
Noncondensable gases ____.
condense readily under normal atmospheric conditions
are undesirable in a refrigeration system
help in pulling a vacuum
are desirable in a refrigeration system
25
A DOT-approved recovery tank should never be filled to more than _____________.
80% of it's liquid capacity
80% of it's tare weight
80% of it's vapor capacity
80% of it's maximum cylinder weight
26
Operating the compressor while in a deep vacuum is allowable to remove water trapped in the oil
False
True
27
A multiple evacuation means that ____.
you connect three vacuum pumps to a system and pull a vacuum
pull a vacuum multiple times adding nitrogen between each
more than one unit is running before a vacuum is pulled
you pull a vacuum on 3 different systems at the same time
28
high side pressure converted to sat. tempand temp. of the liquid line difference
Subcool
Superheat
29
The additional rejection of heat (or cooling of refrigerant) after the change in state in the condenser is called
Superheat
Subcool
30
High superheat and low subcooling indicate
system undercharge
system overcharge
inefficient compressor
restriction in the liquid line
31
The oil in a vacuum pump should be changed before each use.
False
True
32
The synthetic oil most commonly used with HFC refrigerants is
Polyoester
PolyAlkalineGlycol
Alkybenzene
Mineral Oil
33
As refrigerant vapor is removed from a supply cylinder, the pressure in the cylinder will
fluctuate with the ambient pressure
fall
rise
stay the same
34
If you do not have a financial interest in the company you do not have to be EPA certified.
False
True
35
When adding refrigerant vapor to a operating system, the compressor must be running.
True
False
36
When adding liquid refrigerant into the high-side, the compressor is running.
False
True
37
Fractionation occurs when ____.
when only a fraction of the total charge has been added
the operating pressures of a system increase
both a and c are correct
some of the refrigerant boils/condenses before the rest
38
To clean refrigerant by the use of filter dryers and oil separators is called ____.
recycle
recovery
reclaim
renew
39
A de minimus release is _____________
no more than 10 oz
the minimum needed to perform the job
whatever you can get away with
1 oz
40
Charging a refrigeration system refers to ____.
adding refrigerant to a system
removing refrigerant from a system
cleaning the refrigerant
vaporizing the refrigerant
