Assignment   8 Refrigeration and Air Conditioning Textbook Assignment: Engineman 1&C, NAVEDTRA 10543-E1, Pages 6-1 through 7-4 Learning Objective: Indicate how the output of reciprocating refrigeration compressors can be controlled and point out some of the precautions and practices that must be followed when maintaining compressor  condensers,  and  thermostatic expansion  valves. Question  8-1  is  to  be  judged  True  or False. 8-1. The  output  of  most  high  speed reciprocating  compressors  is  controlled  by loading  and  unloading  the  compressor cylinders. 8-2. In  figure  6-8  of  your  textbook,  what  will happen  when  an  increase  in  oil  pump pressure causes the piston of the capacity control  valve  to  move  against  spring  A? 1. More cylinders will become loaded and the  compressor  output  increases 2. More  cylinders  will  become  unloaded and  the  compressed  output  decreases 3. The  regulating  valves  will  relieve the  oil  pressure 4. The  compressor  output  will  remain the same 8-3. Which  of  the  following  precautions  should you  take  when  disassembling  and reassembling  a  compressor  unit? 1. Carefully  disassemble  and  remove  the parts,   noting  the  correct  relative positions  so  errors  will  not  be  made reassembling 2. Make  sure  that  all  parts,  including those  being  replaced  or  reinstalled, are  free  of  dirt  and  moisture 3. Apply  compressor  oil  freely  to  all bearings  and  rubbing  surfaces  of  the parts being replaced or reinstalled 4. Each of the above 8-4. An  air  compressor  has  been  overhauled. What is the first step you should take to remove  the  air  from  a  compressor? 1. Disconnect  the  connection  in  the discharge  gage  line  between  the stop  valve  and  the  compressor 2. Disconnect  the  connection  on  the compressor  suction  line 3. Start  the  compressor  and  let  it  run until a vacuum is obtained 4. Remove  all  oil  from  the  compressor crankcase Question 8-5 is to be judged True or False. 8-5. R-12  is  an  excellent  solvent. It has the ability  to  loosen  and  remove  any  foreign matter  with  which  it  comes  in  contact within  a  refrigeration  system. 8-6. In  which  of  the  following  parts  would  air that  enters  a  refrigeration  plant  tend  to collect? 1. Upper  part  of  the  receiver 2. Upper  part  of  the  condenser 3. Inlet  end  of  the  condenser 4. Downstream  end  of  the  cooling  coil 8-7. In  a  refrigeration  system,  what  is  the purpose of the purge valve at the top of the  condenser? 1. Take  out  unpleasant  fumes  from  the refrigerant 2. Vent  off  excess  refrigerant  during  an emergency 3. Remove  any  air  that  may  accumulate  in the  system 4. Permit  the  opening  of  the refrigerating  system  for  cleaning  and inspecting 48