TM 5-4320-215-12 Section IV.  OPERATION UNDER UNUSUAL CONDITIONS 20.  Operation in Extreme Cold (Below O°F.) a.    General.    Operation  of  the  pumping  unit  in extreme   cold   requires   special   precautions   and   extra servicing if proper operation is to be achieved. b.    Fuel  System.    Keep  the  fuel  tank  full  at  all times.    Service  the  fuel  pump  sediment  bowl  and  fuel strainer daily (TM 5-2805-209-12). c.    Lubrication.    Lubricate   the   pumping   unit   in accordance with the current lubrication order. d.  Electrical System.  Before starting the engine, wipe  the  engine  electrical  system  components  free  of ice and moisture.  Do not disturb electrical wiring since it becomes  brittle  with  extreme  cold.    Allow  the  wiring  to warm  up  before  attempting  to  bend  it.    To  lessen  the possibility  of  damage  to  the  batteries  and  to  increase efficiency, be sure that the batteries are fully charged. Caution Run the engine for approximately 1 hour    after    adding    water    to    the batteries.    This  will  permit  added water   to   mix   with   the   electrolyte and prevent freezing. e.        Pump.        When    operating    the    unit    in    a temperature   below   0°   F.,   the   use   of   warm   water   in priming the pump will thaw ice films on the impeller and seal   the   prevent   damage.      Do   not   use   hot   water   in extremely   cold   weather   because   this   may   result   in cracking   the   chamber.      When   not   in   use,   drain   the pump.  If water is allowed to stand in the pump, freezing may burst the chamber. 21.  Operation in Extreme Heat a.  General.  Operation of the pumping unit under extremely  high  temperatures  requires  special  servicing and  precautions.    If  the  unit  is  to  be  operated  indoors, make sure the ventilation is adequate. b.  Fuel System.  Do not fill the fuel tank too full. Allow sufficient room for fuel expansion. c.    Lubrication.    Lubricate   the   pumping   unit   in accordance with the current lubrication order. 22.  Operation in Dusty or Sandy Areas a.  General.  If the installation of the pumping unit is permanent, erect a protective shelter for the unit.  In temporary     installations     take     advantage     of     natural barriers as much as possible.  Keep the unit as clean as possible. b.    Lubrication.    In  dusty  or  sandy  areas,  the  oil filter  and  air  cleaner  must  be  serviced  more  frequently than  under  normal  conditions.    For  service  of  the  oil filter and air cleaner, refer to TM 5-280-209-12.  Be sure that   the   lubricant   containers   are   tightly   sealed   and stored  in  an  area  as  free  as  possible  from  dust  and sand. c.  Fuel System.  Take the necessary precautions to   keep   dirt   and   grit   from   entering   the   fuel   system. Clean   the   fuel   strainer   each   time   the   fuel   supply   is replenished (TM 5-2805209-12). 23.  Operation Under Rainy or Humid Conditions When   the   pumping   unit   is   operated   outdoors, erect  a  shelter,  if  possible,  to  protect-the  unit.    If  the erection of a shelter is not possible, keep the pumping unit  covered  with  a  canvas  or  other  waterproof  device when inoperative.  Remove the cover during dry periods and allow the unit to dry out.  Keep the fuel tank full to prevent forming of condensation. 24.  Operation in Salt Water Areas a.  General.  Salt water causes a corrosive action on   metal.      Care   must   be   taken   to   avoid   contact   of equipment with salt water.  If the unit is exposed to salt water, wash the unit frequently with fresh water. b.    Painting.    Paint  all  exposed  metal  surfaces Refer to TM 9-2851.  Coat all exposed polished surfaces with  standard-issue,  rustproofing  material,  if  available, or cover with a light coat of grease 25.  Operation at High Altitudes The    pumping    unit    is    designed    to    operate    at elevations   up   to   5,000   feet   above   sea   level   without special service or adjustment. For maximum 16