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1. Low compressor head pressure in a refrigeration system can be caused by which of the following?


2. If the running suction pressure at the refrigeration compressor of a TXV controlled air-cooled refrigeration system is below normal, which of the following can be a cause?


3. During tests to discover why a refrigeration compressor is running continuously, it is determined that the refrigerated space temperature is slightly above normal without ever reaching the desired minimum temperature. Suction and discharge pressures are normal for the corresponding box temperature. In this situation, what should you suspect?


4. When a refrigeration compressor motor fails to start, the FIRST thing that should be checked for is what?


5. If the refrigeration compressor crankcase is sweating or frosting and is operating with an unusual noise, what is most likely the cause?


6. If a refrigeration system were short of refrigerant, besides an elevated box temperature, what would be an observable symptom?


7. If a refrigeration compressor were short cycling on the low pressure cutout switch, what is the most probable cause?


8. If a refrigeration system, equipped with a reciprocating compressor, has a liquid-line solenoid valve that is leaking during the 'off' cycle, what would this cause?


9. A refrigeration unit will tend to short cycle when operating under what conditions?


10. If a refrigeration compressor had developed a slightly high suction pressure accompanied with an abnormally low suction temperature, the problem could be a result of which of the following?


11. An excessive charge of refrigerant in a thermostatically controlled, air-cooled, refrigeration system using a TXV as an expansion device can cause which of the following?


12. If a refrigeration compressor using a thermostat as a primary controller is running continuously without significantly lowering the temperature in the refrigerated space, which of the following is most likely the trouble?


13. In a refrigeration system, the push-pull technique can be used for the recovery of the refrigerant in what state?


14. What must be done, at a minimum, before a system can legally be opened up for repairs while adhering to the prohibition against the venting of halogenated fluoro-carbon refrigerants to the atmosphere?


15. What is the correct color coding of refrigerant recovery cylinders regardless of the refrigerant contained within?


16. Which recovery procedure should be used to minimize the loss of oil from the system during the recovery of refrigerant from small appliances such as a water cooler?


17. What is true concerning highly contaminated refrigerant recovered from burned out small appliances?


18. Technicians servicing small refrigeration appliances can employ what type of recovery equipment?


19. If passive recovery is used on a small appliance fitted with a capillary tube as a metering device with a non-operating compressor, the recovery should be made through what means?


20. Minor repairs may be performed on low pressure refrigerant systems without recovering the refrigerant charge if the pressure in the system is raised to atmospheric. How may this be accomplished?


21. The most cost-effective method of recovering refrigerant from a low pressure chiller with more than 500 lbs of refrigerant and to meet EPA requirements is to recover the refrigerant using what protocol?


22. Why is a purge recovery unit typically fitted on low pressure centrifugal chillers?


23. Before charging a refrigeration unit, unless quick disconnect fittings are used, the refrigerant charging hoses should be prepared in what way?


24. Concerning the charging of refrigerant into a vapor compression refrigerating system, which of the following is true?


25. How should small appliances with less than three pounds of refrigerant be charged with refrigerant?


26. Charging liquid HCFC-123 into a system under a deep vacuum could cause what to happen unless necessary precautions are taken?


27. When a refrigeration system is being topped off with a small amount of refrigerant through the low side with the compressor running, what should be done?


28. Which of the valves listed is normally closed when charging the refrigeration system through the high side?


29. Coast Guard Regulations (46 CFR Part 58) require a method for the relieving pressure of an over pressurized refrigeration system. Which of the following statements complies with these Regulations?


30. Coast Guard Regulations (46 CFR Part 113) require refrigerated spaces that can be locked from the outside and that cannot be opened from the inside to have an audible alarm. Where is the audible alarm required to be?


31. With regards to shipboard refrigeration systems, after July 1, 1992, what action became illegal?


32. Refillable tanks used to ship CFC and HCFC refrigerants or used to recover these refrigerants must meet the standards of what entity?


33. According to 46 CFR, Part 58, for protection purposes, what is required of all refrigeration systems?


34. What would be an example of a small appliance as defined in the EPA Clean Air Act rules?


35. Which best defines a "Type I" small refrigeration appliance according to the EPA Regulations Section 608?


36. If you find the pressure of a refrigeration system containing a Class I or Class II refrigerant to be opened for the accomplishment of repairs is 0 psig, what must be done?


37. EPA Clean Air Act rules permit refrigerant to be released to the atmosphere under which of the following conditions?


38. All shipboard personnel responsible for the maintenance and repair of air conditioning systems using refrigerants covered under the EPA Clean Air Act venting prohibition, must be certified through an approved Environmental Protection Agency (EPA) program to do which of the following?


39. When recovering R-12 from a small appliance with a working compressor, using a recovery device manufactured after November 15, 1993, what percentage of the remaining charge must be removed from the system?


40. Persons recovering refrigerant from small appliances must be certified as what type of technician under the EPA Clean Air Act rules?


41. According to the EPA Clean Air Act rules, what is true concerning refrigerant leaks in a small hermetically sealed shipboard water cooler with a 20 ounce charge weight?


42. Within the territorial limits of the United States, violations of the Clean Air Act of 1990, that includes the intentional release of R-11, R-12, R-22 and other related class I or class II substances may result in fines for each violation per day of what amount?


43. For safe storage, the maximum allowable temperature to which refrigerant bottles should be exposed is what temperature?


44. Personnel servicing refrigeration systems and subject to the exposure to commonly used refrigerants should wear what type of personal protective equipment?


45. In the presence of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants decomposes and form what chemical substance?


46. Why can CFC or HCFC refrigerants leaking into a confined space or in limited surroundings cause suffocation?


47. When repairing a refrigeration system, a swaging tool set would be used to carry out which of the following operations?


48. What is the purpose of running a refrigeration compressor in short intermittent spurts or throttling the suction isolation valve when starting the system after a prolonged shutdown?


49. When starting a reciprocating refrigeration compressor that has been shut down for a period of time, you should manually throttle which valve?


50. When opening or closing compressor service and line isolation valves on a typical refrigeration system that is fitted with packed valves, what must you do?


51. In an air conditioning system, what is the name of the chamber where the duct-work originates?


52. In a two stage centrifugal air conditioning system, the liquid refrigerant passes through the condenser directly to what component?


53. A reheater in an air conditioning system performs what function?


54. What is one benefit of Maintenance of proper air circulation in an air conditioned cargo space?


55. In general, the thermal bulb for a thermal expansion valve used in a reciprocating air conditioning system is usually charged with what substance?


56. To prevent the unnecessary loading of an air conditioning system while maintaining the designed dry bulb temperature and relative humidity in an air conditioning system, what should be done?


57. Which of the following methods is normally used to control the circulated air temperature of an air conditioning system using chilled water circulation?


58. For the proper control of the air temperature in an air conditioning system using chilled water circulation, which of the listed conditions should remain constant regardless of load changes?


59. Which of the processes listed would be the most satisfactory method to use to lower the humidity of the air being circulated by an air conditioning system?


60. A room humidistat initiates the lowering of the humidity of the conditioned supply air to a space, while the actual process is accomplished by what means?


61. In an air conditioning system, moisture is removed from the air by what means?


62. Which of the following is true concerning the class "A" air conditioning system shown in the illustration as used to condition the air of large public spaces?


63. To add small amounts of refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through a particular valve and in a particular state. What valve and state combination is correct?


64. To add refrigerant to the high side of an air conditioning system, you should close the king valve and introduce the refrigerant through what valve in what state?


65. When pumping down an air conditioning system to test the low pressure cutout switch, assuming that the compressor is running, what should be done to initiate the test?


66. The compressor used in a water-cooled air conditioning system is short cycling. A service check determines that the suction pressure remains above the normal cut-in point during cycling and that the discharge pressure rapidly builds up to the cut-out point while running and gradually falls to the cut-in point during the off cycle. What is likely the cause?


67. Concerning the arrangement of equipment and associated hoses shown in the illustration, what statement is true?


68. The surging that occurs in a centrifugal air conditioning compressor is a result of what conditions?


69. In an air conditioning system, low discharge head pressure associated with a reciprocating compressor can be the result of what condition?


70. The air temperature associated with a direct reciprocating air conditioning plant is found to be too warm, and the compressor is not operating. A service check determines the compressor suction pressure to be above the normal cut-in point, with a normal head pressure, and high evaporator superheat. Which of the following could be the cause of this problem?


71. Sludge may form in the crankcase of an air conditioning compressor as a result of what condition?


72. As shown in the illustrated LP centrifugal chiller high efficiency purge recovery unit piping schematic, what statement is true concerning the vacuum pump?


73. Concerning the operation of refrigeration systems, frosting or sweating of a liquid line is usually indicative of what condition?


74. If increasing the cooling water flow to a refrigeration condenser fails to lower the condenser pressure, the probable cause may be due to what condition?


75. Which of the conditions listed could cause excessively low refrigerant pressure at the compressor suction of a TXV controlled refrigeration system?


76. In an operating, water-cooled, multi-box refrigeration system, both low discharge and high suction pressures are being simultaneously experienced. The probable cause for this condition is which of the following?


77. High suction pressure accompanied by low suction temperature to a refrigeration system compressor is caused by which of the following?


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