RMO Final 2 Flashcards
The advantage of forced draft cooling tower over natural draft cooling towers is:
Smaller tower size
That it uses less water
That it improves power
efficiency in water tower
Reduced energy cost
Smaller tower size
Which of the following best describes the purpose of a Halide torch?
Heat, copper and brass fittings for soldering
A safety light
To Locate CO2
To Locate Freon leaks
To Locate Freon leaks
When using a halide torch to test for a strong leak in a Freon system the color of the flame will
turn?
Pink
Blue
Green
Yellow
Blue
Which of the following refrigerants are designated 718?
Propane
Ammonia
Water
Air
WATER
One of the following refrigerants has operating pressures that exceed 1000 PSIG:
Ammonia
Sulfur dioxide
R-114
R-744
R-744
Which of the following best describes R-22?
Toxic
Boiling point at O PSIG equal to -21 degrees Fahrenheit
Odorless and Colorless
Leaks detected with Nessler’s solution
Odorless and Colorless
Which refrigerant does the number 744 designate?
Ammonia
CO2
R-12
Water
CO2
Which of the following best describes the volume of a refrigerant, as its operating pressure decreases?
Increases
Decreases
Stays the same
Is affected by atmospheric pressure
Increases
An R-12 system is mistakenly charged with R-22. What possible affect will it have on the system?
Damage the expansion valve
Overload the compressor motor
Overheat the evaporator
Provide insufficient sub-cooling
Overload the compressor motor
How many BTU’s must be added to one pound of water in order to vaporize the entire quantity?
144
970
1310
1
970
Which of the following is used to measure sensible heat?
Psychrometer
Pressure gauge
Thermometer
Ohm meter
Thermometer
Which of the following is needed to change the state of substance?
Superheat
Sensible heat
latent heat
Radiation
latent heat
Which form of heat transfer requires physical contact?
Radiation
Conduction
Evaporation
Convection
Conduction
Two refrigerating systems (A+B) are each absorbing 800 BTU’s per minute in their evaporators. System “A” has an evaporator temperature of 15 degrees Fahrenheit with a corresponding pressure of O PSIG. System “B” has an evaporator temperature of 35 degrees Fahrenheit with a corresponding pressure of 17 inches of mercury. What are the capacities of these two systems?
System A is 2 tons, System B is 6 tons
System A is 6 tons, System B is 2 tons
System A is 4 tons, System B is 4 tons
System A is 5 tons, System B is 3 tons
System A is 4 tons, System B is 4 tons
Which latent heat is added or removed from a substance, which of the following remains constant?
Pressure
Temperature
BTU content
Physical state
Temperature
Convert 10 PSIG to the corresponding pressure in PSIA:
15
20
30
24.7
24.7
The units of pressure indicated on a compound gauge are:
Pounds of atmospheric pressure
Inches of mercury above atmospheric pressure
Inches of pressure
Pounds per square inch above atmospheric pressure, inches of vacuum below atmospheric pressure
Pounds per square inch above atmospheric pressure, inches of vacuum below atmospheric pressure
The unit of vacuum indicated on a compound gauge is:
Inches of water
Feet of water
Microns
Inches of mercury
Inches of mercury
Which of the following values of pressure is not equivalent to atmospheric pressure?
A barometric reading of 29.92” Hg
0 PSIG
14.7 PSIA
29.9 inches of vacuum
29.9 inches of vacuum
Which of the following units of pressure are considered absolute values?
PSIG & PSIA
“Hg (barometric) & “Hg (vacuum)
PSI & PSIG
PSIA & “Hg (barometric)
PSIA & “Hg (barometric)
What effect will moving to a higher elevation have on barometric readings?
Increased pressure
Decreased pressure
No change
20% increase
Decreased pressure
Water tube leaks in a low-pressure chiller can be found by:
Thermographic test
Circulating Nessler’s solution
Hydrostatic Test
Dielectric Test
Hydrostatic Test
When an air conditioning system is operating efficiently, the finned coils of the evaporator should be:
Dry
Wet
Frosted
Partly frosted
Wet
Which of the following would be considered a benefit associated with indirect refrigeration systems?
Less cost to erect
Less cost to operate
East of operation
Building occupant safety
Building occupant safety
- In a particular Freon compression system, the compressor is running continuously. How will the
suction pressure be affected as the evaporator load decreases?
Increase
Decrease
Remain steady regardless of changes in the load
First decrease and then steadily increase
Decrease
What type of refrigeration system is mostly likely to leak into the building spaces that are being cooled?
Indirect systems
Direct systems
Indirect closed systems
Cascade systems
Direct systems
Which of the following best describes how an evaporator absorbs heat from air or water?
Heat is conducted from the air or water to the refrigerant
Heat is conducted from the refrigerant to the air or water
Refrigerant boils to a low pressure gas
Refrigerant boils to a high pressure gas
Refrigerant boils to a low pressure gas
