NYC RMO EXAM, CHAPTER 13 (Refrigeration Oil and Lubrication Systems) Exam Questions and Complete Solutions

NYC RMO EXAM, CHAPTER 13 (Refrigeration Oil and Lubrication Systems) Exam Questions and Complete Solutions 13.01.) Which of the following properties would a good quality refrigerant oil include? - Answer: Non-corrosive and harmless quality to metals 13.02.) Which of the following properties should refrigerating oil have? - Answer: No moisture content, no paraffin wax content, and a high flash point 13.03.) How many kinds of lubricating oil are used in a horizontal double acting compressor? - Answer: Two 13.04.) What percentage of oil travels through the refrigerant system while it is operating? - Answer: 10% 13.05.) What function does the oil lantern perform inside of a stuffing box type seal? - Answer: Act as a spacer to hold oil 13.06.) A two cylinder, vertical, single stage compressor is equipped with a gear type oil pump. For good performance of this equipment, the oil discharge pressure should range approximately from? - Answer: 10 to 30 PSIG above the suction pressure 13.07.) The term viscosity refers to what property refrigerant oil? - Answer: Internal friction 13.08.) Oil foaming in the crankcase of a compressor is caused by? - Answer: A sudden drop in crankcase pressure 13.09.) A new compressor has just been installed in a refrigeration plant. What amount of oil should be charged into it? - Answer: Slightly more than normal 13.10.) At what location in the refrigeration cycle should the oil separator be installed? - Answer: In the discharge line as far away from the compressor as possible 13.11.) It has been determined that the oil level in a particular refrigeration system is low. By which of the following methods should additional oil be charged into the system? - Answer: Pumping it into the compressor crankcase 13.12.) Which of the following statements regarding the flashpoint of refrigerant oil is most correct? - Answer: Should take place at a temperature which is higher than the compressor discharge temperature 13.13.) Of the following, the primary reason for the installation of a crankcase breather line is? - Answer: To allow refrigerant to return to the compressor suction 13.14.) A refrigeration system has a reciprocating compressor. When is the oil heater energized? - Answer: As the compressor cycles off 13.15.) Which type of lubrication system is recommended for use on smaller capacity systems, but is usually unsatisfactory for modern high speed compressors? - Answer: Splash type system 13.16.) If paraffin-based oil was to foul an evaporator, how would you remove the wax? - Answer: Heating up the coil and pumping it out 13.17.) If an operator erroneously charged a refrigeration system with a parrafin-based oil, how would it affect the system? - Answer: The evaporator would become fouled with wax 13.18.) When a reciprocating compressor is operating the crankcase pressure is closest to which of the following? - Answer: Evaporator pressure 13.19.) In a compression refrigeration system, how would the evaporator be affected if it becomes oil logged? - Answer: Loss of refrigeration effect