TM 9-4940-342-14&P b.  For   300   GPH,   one   gun   with   steam   vapor operation proceed as follows. (1)  Attach  one  cleaning  gun  and  hose  with  a number 1 drill hex or flat high pressure vapor nozzle installed  to  discharge  valve  (32).  Open  valve  and close other valve. (2)  Set   selector   valve   (8)   at   its   horizontal position. (3)  Start unit. Turn pump control switch (4) to ON. (4)  Set  pressure  and  temperature  control  valve (34) to approximately 325°. c.  For 300 GPH, two gun steam vapor operation, proceed as follows. (1)  Attach two cleaning guns and hoses with a number 1 drill hex or flat high pressure vapor nozzle installed  on  the  discharge  valves  (32).  Open  both valves. (2)  Set selector valve (8) at its vertical position. (3)  Start unit. (4)  Set  pressure  and  temperature  control  valve (34) to approximately 325°. d.  For 600 GPH, one gun steam vapor operation, proceed as follows. WARNING Due  to  extreme  pressure  velocity  at  600  GPH,  two operators are recommended to be present during 600 GPH operating procedures. (1)  Attach  one  cleaning  gun  and  hose  with  a 5/16-inch   hex   or   flat   high   pressure   vapor   nozzle installed to one discharge valve (32). Open this valve and close the other valve. (2)  Set selector valve (8) at its vertical position. (3)  Start unit. (4)  Set  pressure  and  temperature  control  valve (34) to approximately 325°. e.  For   600   GPH,   1   gun   hot   rinse   operation, proceed as follows. (1)  Attach  one  cleaning  gun  and  hose  with  a 25°   high   pressure   rinse   nozzle   installed   to   one discharge  valve  (32).  Open  this  valve  and  close  the other valve. (2)  Set selector valve (8) at its vertical position. (3)  Start unit. (4)  Set  pressure  and  temperature  control  valve (34) to approximately 185-200°. f.   For   600   GPH,   1   gun   cold   rinse   operation, proceed as follows. WARNING Due to extreme pressure velocity at 600 GPH, two operators  are  recommended  to  be  present  during operating at 600 GPH. (1)  If  a  complete  cold  rinse  is  desired,  attach one cleaning gun and hose with a 25° high pressure rinse  nozzle  installed  to  one  discharge  valve  (32). Open this valve and close other valve. (2)  Set   the   selector   valve   (8)   at   its   vertical position. (3)  Start unit. (4)  Set  pressure  and  temperature  control  valve (34) to desired temperature, or leave burner off (see para 2-8, step j). Section V. OPERATION UNDER UNUSUAL CONDITIONS 2-12.  Operation in Extreme Cold a.  In extreme cold, the unit must be placed where running water is available and where incoming water lines are insulated. NOTE Care should be exercised in placing hoses or pipes where they will not freeze and stop water from flowing b.  Place   an   automatic   damper   in   the   stack   to prevent cold air from coming down and freezing the coil when the cleaner is not in operation. c.  Enclose   the   cleaner   in   a   small   room   with temperature  above  the  freezing  point.  Heat  of  the room    should    be    thermostatically    controlled    to minimize    damage    caused    by    unexpected    cold weather. d.  After every operation in cold weather, drain all fluids from steam cleaner and hoses. (1)  Drain   soap   through   solution   tank   drain valve (14). (2)  Drain water through the reservoir overflow and drain (23). (3)  Drain  heating  coil  through  air  dome  drain valve (31) and discharge valves (32). (4)  Drain pump through valves (17 and 22). WARNING When  storing  in  freezing  weather  conditions  unit must be drained thoroughly, and it is recommended plumbing   system   be   charged   with   a   50   percent solution   of   permanent   type   antifreeze.   Antifreeze should  be  used  when  unit  is  NOT  in  service  for prolonged periods or being transported to extremely cold areas. 2-13.  Operation in Extreme Heat a. There are no precautions to be taken when operating the steam cleaner under extremely hot conditions. 11