Assignment 8
Refrigeration and Air Conditioning
Textbook Assignment: Engineman 1&C, NAVEDTRA 10543-E1, Pages 6-1 through 7-4
Learning Objective: Indicate how the
output of reciprocating refrigeration
compressors can be controlled and point
out some of the precautions and practices
that must be followed when maintaining
compressor condensers, and thermostatic
expansion valves.
Question 8-1 is to be judged True or
False.
8-1.
The output of most high speed
reciprocating compressors is controlled by
loading and unloading the compressor
cylinders.
8-2.
In figure 6-8 of your textbook, what will
happen when an increase in oil pump
pressure causes the piston of the capacity
control valve to move against spring A?
1.
More cylinders will become loaded and
the compressor output increases
2.
More cylinders will become unloaded
and the compressed output decreases
3.
The regulating valves will relieve
the oil pressure
4.
The compressor output will remain
the same
8-3.
Which of the following precautions should
you take when disassembling and
reassembling a compressor unit?
1.
Carefully disassemble and remove the
parts, noting the correct relative
positions so errors will not be made
reassembling
2.
Make sure that all parts, including
those being replaced or reinstalled,
are free of dirt and moisture
3.
Apply compressor oil freely to all
bearings and rubbing surfaces of the
parts being replaced or reinstalled
4.
Each of the above
8-4.
An air compressor has been overhauled.
What is the first step you should take to
remove the air from a compressor?
1.
Disconnect the connection in the
discharge gage line between the
stop valve and the compressor
2.
Disconnect the connection on the
compressor suction line
3.
Start the compressor and let it run
until a vacuum is obtained
4.
Remove all oil from the compressor
crankcase
Question 8-5 is to be judged True or
False.
8-5.
R-12 is an excellent solvent.
It has the
ability to loosen and remove any foreign
matter with which it comes in contact
within a refrigeration system.
8-6.
In which of the following parts would air
that enters a refrigeration plant tend to
collect?
1.
Upper part of the receiver
2.
Upper part of the condenser
3.
Inlet end of the condenser
4.
Downstream end of the cooling coil
8-7.
In a refrigeration system, what is the
purpose of the purge valve at the top of
the condenser?
1.
Take out unpleasant fumes from the
refrigerant
2.
Vent off excess refrigerant during an
emergency
3.
Remove any air that may accumulate in
the system
4.
Permit the opening of the
refrigerating system for cleaning and
inspecting
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