4-27. A well-maintained and properly used tumbler will dry a load of laundry in what minimum amount of time? 1. 10   minutes 2. 20   minutes 3. 30   minutes 4. 40   minutes 4-28. Steam kettles safety valves are set to  release  at  what  pressure? 1. 15   psig 2. 25   psig 3. 35   psig 4. 45   psig 4-29. Varied operating conditions of the distilling plants are a primary cause  of  which  of  the  following problems? 1. Changes  in  feed  level 2. Scaling  of  evaporator  tubes 3. Improper liquid level in the first-effect  tube  nest 4. Excessive steam pressure 4-30. You are making adjustments on distilling  plant  controls  to  bring heat  and  fluid  conditions  into balance. Which of the following techniques  should  you  use? 1. Adjust all controls simultaneously 2. Adjust all heat controls one at a time and quickly 3. Adjust controls one at a time and  in  small  adjustments 4. Adjust each control at 10-minute  intervals 4-31. Which of the following factors is NOT likely to cause a decrease in the  distilling  plant's  efficiency? 1. Air  leaks  in  the  first-effect tube  nest 2. Low  vacuum  in  the  last-effect shell 3. Dirty circulating water strainer 4. No undue deposits inside the tubes 4-32. You should inspect distilling plant steam orifices a minimum of how often? 1. Monthly 2. Twice a year 3. Annually 4. At each overhaul 4-33. From  which  of  the  following  sources should you take water to be used to desuperheat  live  steam? 1. The  first-effect  tube  nest drain  pump 2. The second-effect tube nest drain  pump 3. The freshwater supply 4. The  steam  feed  system 4-34. Fluctuations in the first-effect steam  pressure  and  temperature  will cause  similar  fluctuations  in  which of the following parts of the plant? 1. The  second-effect  shell  only 2. The  steam  supply  line  only 3. The  water  levels  only 4. The  entire  plant 4-35. When you keep the vacuum in the first-effect  tube  nest  of  a distilling plant as high as possible,  you  will  reduce  which  of the  following  factors? 1. The  amount  of  brine  pumped overboard 2. The  pressure  rate  of  the  steam lines 3. The rate of evaporator tube scaling 4. The  rate  of  distillate formation 4-36. When you cannot feed water into the first-effect tube nest of a distilling  plant,  you  should  look for which of the following causes? 1. Scale deposits in the air ejector 2. Scale deposits in the vapor feed  heater 3. Obstructions  in  the  feed  line 4. Each of the above 29