4-9.
What technique must you use to
clean the sensing elements in the
humidistats?
1. Use of a soft brush
2. Use of gently blown air
3. Use of a spray of soap and
water solution
4. Use of a hard brush
4-10.
To correct a low condensing
pressure in an operating
refrigeration system, you should
perform which of the following
actions?
1.
Reduce the water supply
2.
Increase the water pressure
3. Clean the valves and the valve
seats
4.
Adjust the high-pressure cutout
switch
4-11.
Insufficient refrigerant in a
refrigeration plant may cause which
of the following problems?
1.
High discharge pressure
2. Low suction pressure
3. Frosting of the crankcase
4. High temperature of the
overboard water
4-12.
Which of the following actions
should you take to correct a low
condensing pressure in a
refrigeration system?
1.
Add refrigerant
2. Purge the condenser
3. Increase the compressor speed
4. Adjust the thermostatic
expansion valve
4-13.
In an R-12 refrigeration plant, a
compressor runs continuously.
What
is the probable cause?
1. An open solenoid valve switch
2. An inadequate supply of
refrigerant
3. Clogged condenser tubes
4. An excess of liquid refrigerant
4-14.
Which of the following symptoms
indicates that an inadequate supply
of water is passing through the
condenser of a refrigeration plant?
1. Excessively low temperature of
the overboard water and low
discharge pressure
2.
High suction pressure and high
temperature of the suction line
3. High condensing pressure and
compressor short cycling on the
high-pressure switch
4.
High suction line temperature
and high discharge pressure
4-15.
The cut-in point is set too high on
the low-pressure control switch of
an R-12 refrigeration system. How
will this effect the functioning of
the compressor?
1.
It will short cycle
2.
It will not operate
3.
It will operate unloaded
4.
It will operate continuously
4-16.
Which of the following conditions
is probably caused by liquid
refrigerant slugging back to the
compressor crankcase of a
refrigeration system?
1.
Bubbles in the refrigerant
2. A sudden loss of oil from the
crankcase
3. The compressor continues to
operate unloaded
4.
Failure of oil to return to the
compressor crankcase
4-17.
Aboard Navy ships, in which of the
following situations would you most
likely use MP air?
1.
To clean machinery
2.
To start diesel engines
3.
To operate pneumatic tools
4.
Each of the above
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