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SEAL REFRIGERATION QUESTIONS 1.On a single acting reciprocating compressor, what is the function of a duel control device? ans A It allows automatic starts and stops B It allows the starting and stopping of the unit from several locations C It allows constant speed control and automatic starts and stops D
It allows the unit to be either manually or automatically operated 2. If a system were using an automatic expansion valve, what would the constant pressure be maintained at? ans
A.
The evaporator
C The evaporator outlet
B.
The condenser outlet
D. The condenser inlet 3.
What is the main advantage of a cascade refrigeration system?
A Does not deplete
the ozone layer B Capable of
reaching very low temperature
C. Low cost and maintenance D.
All
of the above 4. Choose the statement below, which would prove false about lithium bromide used in absorption systems. ans A It is highly corrosive C. It is non-corrosive B. It is non-toxic D. It has a boiling point 5. What is a sling psychrometer device used to measure? ans A. Absolute humidity C Relative humidity B.
Ambient
air temperature
D Specific gravity 6.
A system using an evaporative condenser operates most efficiently under
what conditions? A when the dry-bulb temperature of air is high B. When the dry-bulb temperature of air is low C. when the wet-bulb temperature of air is high D. When the wet-bulb temperature of air is low 7. The discharge gas from the compressor is what, in a wet-compression refrigeration system. ans
A.
Saturated C
superheated
B. Sub cooled D None
of the above 8. If a refrigeration system were over charged
with refrigerant, what conditions would occur?
A. Increase in capacity and decrease in
suction pressure
B Decrease
in capacity and decrease in suction pressure
C Decrease
in capacity and increase in head pressure
D Increase
in capacity and decrease in head pressure 9.
If a cooling tower circulated 4,300 gpm
of water, what is the cooling capacity in
tons
A. 1,433 tons
C.
3400 tons
B. 650 tons
D. 500 tons 10. What condition would cause a system to not respond to an expansion valve adjustment? ans
A. Excessive compressor motor speed
C. Insufficient water to the condenser
B. Oil in the evaporator
D. None of the above 11. In an absorption system, the generator receives what medium? ans
A. Water
C. Weak Liquor
B. Strong liquor
D.
Condensate 12. Which would have the least effect on the capacity of a water-cooled condenser? ans A. When they are opened and closed by rotation of the crank shaft B. The temperature of the water C. when they are opened and closed by spring tension D. When they are opened and closed by pressure difference 13. What is the volume occupied by a refrigerant under specified conditions of pressure and temperature? ans A. Density C. Specific Volume B. Specific density
D. Volume 14. What should a cooling tower water ph be maintained at? ans
A. 8
C. 10
B. 12
D. 14 15. The absolute Celsius scale is referred to by which temperature scale? ans
A.
Brayton Temperature scale
C. Kelvin temperature scale
B.
Carnot Temperature scale
D. Rankin temperature
scale 16. Which devices control the high side float? ans
A. Evaporator and Condenser
C. Accumulator and condenser
B. Condenser and receiver
D.
Evaporator and receiver 17. In Fahrenheit, what is the equivalent of -15 degrees Celsius? ans A. l0 degrees F C. -- 5 degrees F
B. –6 degrees F D. – 7 Degrees F 18.
If you had a flooded evaporator,
which type of metering device would you use? A. Low side float C. high side float B.
Expansion valve D. capillary tube
19. Choose the formula used to determine the number 0£ cycles of concentration for a cooling Tower? ans A. Cycles = tower water conductivity I tower water chlorides B. Cycles = Makeup water chlorides I tower water chlorides C. Cycles = Tower water chlorides / makeup water conductivity D. Cycles = Tower water chlorides / makeup water chlorides 20. What determines the low side pressure in a refrigeration system? ans A The compressor capacity C. The amount of liquid in the receiver B. The evaporator flow rate D. The amount of load on the system 21. Which seal is not used on a refrigeration system? ans A. Rotary C. Stationary
B. Mechanical
D.
Packing 22.
Which water chemistry test is used to determine cooling tower cycles of
concentration? A.
Chlorides
C. Ph B
Conductivity
D. Hardness
23. Why is a rheostat used on a synchronous motor?
A. To shut off the AC power to the field
B. To adjust the AC power to
the exciter.
C. To vary the power
factor to the load conditions.
D. To adjust the DC power to the fields.
24.
What would happen if you had a sudden drop in the temperature in the
cooling tower of a lithium bromide absorption system? A Crystallization in the system B. Low head pressure in the absorber C. Low pressure in the system D. High head pressure in the absorber 25. What is the function of a heat exchanger in an absorption system? ans A.
Allows the condensate from the generator to heat the strong liquor
B. Allows the
condensate from the generator to heat the weak liquor
C. Allows the strong liquor to heat the weak liquor
D. Allows the weak liquor
to heat the strong liquor 26. Define the term “Refrigerant reclaiming” ans A. Selling reprocessed refrigerant as “reclaimed refrigerant” B. Reprocessing the refrigerant into a new product that can be reused. C. Chemically analyzing and distilling the refrigerant. D. All of the above 27. Which phrase best describes the term “ free air”? ans A. Air at a pressure higher than atmospheric. B. Air at atmospheric conditions. C. Air at a pressure lower than atmospheric D. None of the above. 28. How is the setting on a thermostatic expansion valve rated? ans A. Tons of refrigeration C. Degrees of superheat B. BTU/hr. D. BTU/Min. 29. Which statement describes the operation of a single acting compressor? ans A. The refrigeration gas is compressed on only one side of the piston. B. The refrigerant gas is compressed on only the piston and then the other. C. The piston speed can be manually controlled for better volumetric efficiency. D. None of the above. 30. Which of the following would cause a noisy compressor? ans A. Lack of oil. C. Loose drive coupling B. Dry or damaged seal. D. All of the above. 31. When the evaporator load increases, what happens to the suction pressure of the system? ans A. Flow increases while the pressure remains constant. B. Flow remains constant with a corresponding pressure increase. C. Suction pressure remains constant. D. Flow remains constant with a corresponding pressure decrease. 32. Thermostatic expansion valves are rated in what units of measurement? ans A. Tons of refrigeration. C. Degrees of superheat. B. BTU/min D. None of the above. 33. If a cooling tower has a PH of 7.8 it is: ans A. Highly alkaline C. Highly Acidic B. Slightly acidic D. Slightly alkaline 34. Where would you find flash gas in an efficiently operating system? ans A. In the receiver C. In the evaporator B. In the
condenser
D. In the compressor 35. The capacity of an evaporative condenser is determined by: ans A. The amount of heat the entering air can absorb. B. The amount of air flowing over the coil C. The area of the refrigerant coil surface D. All of the above. 36. The ratio between the actual pressures of the vapor to its saturation pressure in the atmosphere is known as what? ans A. Psychometric effort C. Refrigeration effect. B. Relative humidity. D. None of the above. 37. A cooling tower is circulating 2,850 GPM of water: What is the cooling capacity in tons? ans A. 610 B. 459 C. 950 D. 1,205 38. What conditions can cause high discharge pressure in a system? ans A. Refrigerant overcharge B. An undersized condenser C. Insufficient cooling water to the condenser. D. All of the above. 39. What would frost on the suction line of a system using a high side float indicate? ans A. Oil in the evaporator. B. Low refrigerant charge C. Non-condensables in the system. D. Overcharged system 40. In an absorption system, what would cause the strength of the strong liquor to decrease? ans A. Decrease in the condenser pressure B. Increase in the condenser pressure C. Increase in the load on the evaporator D. Decrease in the load on the evaporator 41. What type of heat exchange occurs at the exterior sides of a cooling tower? ans A. Radiation C. Evaporative B. Conductive D. Convection 42. Which of the following statements is most true regarding the compression ratio of a reciprocating compressor? ans A. Absolute suction pressure / absolute discharge pressure B. Ratio varies according to the conditions under which it operates C. Ratio remains constant under all operating conditions D. Absolute suction pressure / absolute suction pressure 43. If the high side float were to fill with liquid and sink, what would be the result? ans A. The compressor would stall B. The condenser would starve for refrigerant C. The evaporator would starve for refrigerant D. The evaporator would flood with refrigerant 44. In a refrigeration system, what part is considered the low-side? ans A. Between the expansion valve and the condenser B. Between the suction and discharge stop valves C. Between the evaporator and the compressor D. Between the compressor and the king valve 45. What function does the evaporator perform in a refrigeration system? ans A. Absorb heat from the system B. Converts a low pressure liquid refrigerant into a high pressure gas. C. Converts a high pressure gas to a low pressure liquid D. None of the above 46. Why is a horizontal shell and tube condenser more efficient than a vertical shell and tube condenser? ans A. It’s mounted in a horizontal position C. It is easier to clean B. It takes advantage of more cooling air D. Has more than one pass 47. On a two stage system, where should the booster compressor be located? ans A. Between the intercooler and the main compressor B. Between the condenser and the expansion valve C. Between the evaporator and the intercooler D. Between the main compressor and the condenser 48. What is the maximum amount of refrigerant allowed in a 120 lb. Cylinder? ans A. 100 C. 64 lbs. B. 96lbs. D. 85 lbs. 49. One ton of refrigeration equals? ans A. The removal of 25,000 Btu/hr B. The removal of 16,000 Btu/hr C. The removal of 12,000 Btu/hr D. The removal of 11,000 Btu/hr 50. Which statement best defines the operation of a synchronous motor? ans A. Starts AC, operates DC C. Starts on AC, operates AC B. Starts DC, operates AC D. Starts on AC, operates on AC/DC 51. Which statement best defines the operation of the valves of a refrigeration compressor? ans A. They are opened and closed by the rotation of the camshaft B. They are opened and closed by spring tension
C. They
are opened and closed by pressure difference
D. They are opened and closed by external springs 52. Where is oiling required on a centrifugal refrigeration system? ans A. At the shaft end bearings B. At the shaft end bearings and stage separators C. At the shaft end bearings and the rotor D. At the shaft end bearings, rotor and stage separators 53. If water is leaving an efficiently operating induced draft cooling tower, what is the temperature of the water? ans A. At dry bulb temperature of the air B. At the wet bulb temperature of the air C. At the dew point temperature of the air D. Between the wet bulb and the dry bulb temperature of the air 54. What determines the low side pressure in a refrigeration system? ans A. The compressor capacity B. The amount of load on the system C. The amount of liquid in the receiver D. The evaporator flow rate 55. What is the reason for sub-cooling the refrigerant? ans A. To increase its density C. To reduce its density B. Refrigerants cannot be sub-cooled D. To increase the refrigeration effect 56. Which statements below would not cause a noisy compressor? ans A. Flash gas in the expansion valve B. Dry or damaged seal C. Lack of oil D. Loose drive coupling 57. Which type of motor is typically used on condenser and evaporator blowers? ans A. Capacitor start, induction run B. Repulsion start, induction run C. Squirrel cage motor D. Synchronous motor 58. If a reciprocating compressor was run with the suction valve closed and the discharge valve open, what would ans occur? A. Non-condensables would enter the compressor B. The dead pressure would increase C. The compressor head would blow off D. All of the above |