RESIDENTIAL HVAC INSTALLATION EXAM QUESTIONS WITH COMPLETE SOLUTIONS VERIFIED GRADED A+
Clearance tolerances are such that the ordinary clean refrigerant oil can be used satisfactorily in a vacuum pump.
false
The maximum recommended pressure for leak testing is 150 psig on the low-pressure sid...
Clearance tolerances are such that the ordinary clean refrigerant oil can be used
satisfactorily in a vacuum pump.
false
The maximum recommended pressure for leak testing is 150 psig on the low-
pressure side of the system.
true
Noncondensable gases ____.
are undesirable in a refrigeration system
To pull a vacuum means to ____.
lower the pressure in a refrigeration system below atmospheric
A(n) _ pressure could also mean refrigerant vapor is still seeping from the
refrigeration system.
high-rising
A deep vacuum involves reducing the pressure in a refrigeration system to a
micron gauge reading of _ or below.
500 or below.
Micron gauge displays can be electronic analog, digital, or _.
light emitting
A multiple evacuation means that ____.
you pull a vacuum on a refrigeration system more than once, allowing refrigerant or
nitrogen into the system between each procedure
To insure accurate testing, the best material to use for connecting lines to the
vacuum pump and gauge set is ____.
copper tube
The oil in a vacuum pump should be changed after each time it is used.
, true
There are _ microns in 1 mm Hg.
1,000
Air entering a refrigerant system can eventually lead to compressor failure.
true
A micron gauge is used to measure ____.
absolute pressures below 1 mm Hg
The electronic vacuum gage is attached to the system so it can measure the
pressure _ the system.
inside
Moisture in a liquid state must be ____ before it can be removed with a vacuum
pump.
vaporized
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.
false
When using a "standing pressure test" for leak-checking, _ should never be used
since an explosive mixture can be created.
oxygen
When moisture is present in a refrigeration system, it will react with the
refrigerant and the oil to form ____.
acid
A compound gauge ____.
all of the above
The best method of leak checking is when the refrigeration system is ____.
standing with dry nitrogen pressure of 150 psig in the system
At what pressure range does the technician valve off the vacuum pump when
evacuating to a deep vacuum?
500-300 microns
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