TM 5-4320-215-12 operational   efficiency   above   5,000   feet,   it   may   be necessary  to  readjust  the  carburetor.    Refer  to  TM  5- 2805-209-12     for     proper     carburetor     adjustment     at altitudes above 5,000 feet. Section V.  OPERATION OF MATERIEL USED IN CONJUNCTION WITH THE PUMPING UNIT 26.  Fire Extinguisher (Bromochloromethane Type) a.      Description.        A    bromochloromethane    fire extinguisher (fig.  10) is provided with the equipment.  It is a vaporizing, liquid-type, pressurized, trigger-operated pump of 1 quart capacity. b.  Operation.  Remove the fire extinguisher from its  location  and  squeeze  trigger.    Direct  the  stream  at the base of the flame. Warning Be extremely careful when using a bromochloromethane fire extinguisher in an inclosed area.  A poisonous  gas  is  generated  by  the contact of bromochloromethane with    a    heated    metallic    surface. Provide adequate ventilation before   entering   an   inclosed   area where     bromochloromethane     has been used. c.    Refilling  and  Maintenance.    For  refilling  and maintenance, refer to field maintenance. 27.      Fire   Extinguisher   (Monobromotrifluoromethane Type) a.  Description.  The monobromotrifluoromethane type  fire  extinguisher  replaces  the  carbon  dioxide  and carbon  tetrachloride  type  fire  extinguishers  and  in  the past.  It is generally suitable for all types of fire, with the exception  of  fires  involved  with  LOX    (liquid  oxygen) generating equipment.  The fire extinguisher is furnished with a disposable-type cylinder. b.    Operation.    To  operate  the  fire  extinguisher. perform the following operations: (1)  Remove  the  fire  extinguisher  from  its location. (2) Break the seal by pulling the safety pin from the handle. (3) Point the horn at the base of the flame. (4)  Depress  the  trigger  for  discharge  and direct the stream of contents at the base of the fire. (5) Replace with a new cylinder immediately after using. c.    Replacement  of  Cylinder.    To  replace  with  a new cylinder, perform the following operations: (1) Press the lever to release pressure from the old cylinder. (2)   Loosen   the   swivel   valve   coupling   nut and remove the valve assembly from the used cylinder. (3)  Remove  the  instruction  band  from  the used cylinder. (4)   Place   the   new   cylinder   through   the instruction band. (5) Replace the safety pin in the valve and seal with sealing wire. (6)  Attach  the  valve  assembly  and  tighten the    swivel    coupling    nut    on    the    new cylinder and replace the fire extinguisher in the mounting bracket. (7)    Adjust    the    instruction    band    on    the cylinder to show maintenance and operating instructions. d.      Maintenance.      Weigh   the   fire   extinguisher every  6  months  and  replace  the  cylinder  if  the  gross weight has decreased 4 ounces or more.  Lubricate the cylinder  neck  threads  with  1  drop  of  OE  30  oil  before reassembly. 17