TM 5-4110-235-24P Section I.  INTRODUCTION 1.  SCOPE This    manual    lists    repair    parts,    special    tools,    test, measurement   and   diagnostic   equipment   (TMDE),   and other   support   equipment   required   for   operation   and performance    of    organizational,    direct    support,    and general support maintenance of the Refrigeration Unit. 2.  GENERAL a. Section II Repair Parts List.  A list of repair parts authorized  for  use  in  the  performance  of  maintenance. The  list  also  includes  parts  which  must  be  removed  for replacement   of   the   authorized   parts.      Parts   lists   are composed  of  functional  groups  in  ascending  numerical sequence,  with  the  parts  in  each  group  listed  in  figure and item number sequence.  Bulk materials are listed in NSN sequence, as the last group in Section II. b. Section III - Special Tools List.  (Not Applicable.) c. Section   IV   National   Stock   Number   and   Part Number Index.  A list, in ascending numerical sequence, of  all  National  stock  numbers  appearing  in  the  listings, followed  by  a  list,  in  alphanumeric  sequence,  of  all  part numbers    appearing    in    the    listings.        National    stock numbers and part numbers are cross-referenced to each illustration figure and item number appearance. 3.  EXPLANATION OF COLUMNS. The  following  provides  an  explanation  of  columns  found in the tabular listings: a. Illustration.  This column is divided as follows: (1) Figure    Number.        Indicates    the    figure number of the illustration in which the item is shown. (2) Item    Number.        The    number    used    to identify    each    item    called    out    in    the illustration. b. Source, Maintenance, and Recoverability Codes (SMR). (1) Source Code.  Source codes are assigned to  support  items  to  indicate  the  manner  of acquiring  support  items  for  maintenance, repair,  or  overhaul  of  end  items.    Source codes  are  entered  in  the  first  and  second positions of the Uniform SMR Code format as follows: Code Definition PA Item procured and stocked for anticipated or known usage. PB Item   procured   and   stocked   for   insurance purpose because essentiality dictates that a   minimum   quantity   be   available   in   the supply systems. PC Item    procured    and    stocked    and    which otherwise  would  be  coded  PA  except  that it is deteriorative in nature. PD Support  item,  excluding  support  equipment, procured  for  initial  issue  or  outfitting  and stocked  only  for  subsequent  or  additional initial  issues  or  outfittings.    Not  subject  to automatic replenishment. PE Support equipment procured and stocked for initial     issue     or     outfitting     to     specified maintenance repair activities. PF Support equipment which will not be stocked but   which   will   be   centrally   procured   on demand. PG Item   procured   and   stocked   to   provide   for sustained    support    for    the    life    of    the equipment.        It    is    applied    to    an    item peculiar  to  the  equipment  which,  because of probable discontinuance or shutdown of production facilities, would prove uneconomical to reproduce at a later time. KD An  item  of  a  depot  overhaul/repair  kit  and not    purchased    separately.        Depot    kit defined    as    a    kit    that    provides    items required at the time of overhaul or repair. KF An    item    of    a    maintenance    kit    and    not purchased   separately.      Maintenance   kit defined  as  a  kit  that  provides  an  item  that can    be    replaced    at    organizational    or intermediate levels of maintenance. 1