TM 5-3895-374-24-2 6. Check breaching and stack to ensure that they are open and unobstructed. 7. Check    blower    (and    oil    pump    motor,    as    applicable) rotation   by   momentarily   making   contact   of   the   motor starters.  Proper rotation is imprinted on the fan housing and (if supplied) the remote oil pump set assembly. 8. Check operating controls, limit controls, low water cut-off, flame safeguard control reset, high and low gas pressure switches  (if  used)  and  low  fire  interlock  switch  (if  used) and all other applicable interlocks. All contacts should be closed (an exception will be found on jobs using the low gas pressure switch; this switch should be open until the main gas cock is opened).  If a low oil pressure switch is used,  its  contacts  will  remain  open  until  the  oil  pump  is running and the low oil pressure cut-in point is reached. 9. Do not repeatedly recycle the burner, so as to allow any unburned fuel in the combustion chamber. 10. Specific  instructions  relative  to  component  sequencing are    provided    in    the    flame    safeguard    manufacturers bulletin which is included with the documentation shipped with the burner. 11. Proper test equipment must be used in order to achieve maximum system operational reliability and fuel efficiencies.  See page 23 for equipment lists. 12. All   fuel/air   adjustments   should   be   made   to   achieve required  input  rate,  satisfactory  combustion  test  values, flame stability and appearance. 13. Every new burner start up should employ the use of the “Burner  Start  Up  Information  and  Test  Data”  sheets  on pages 41 and 42. Information on Fuel/Air Modes of Operation for Combination Gas/Oil Units General Information Specific   adjustments   and   mechanical   operation   of   the   various modes  of  fuel/air  control  for  straight  gas  and  straight  oil  burners are  included  in  this  manual.    This  information  should  be  used  to properly   adjust   each   fuel   for   combination   gas/oil   units.      The following information is offered as additional guidance. Gas On/Off System Combined with Oil On/Off System The  air  dampers  are  adjusted  and  locked  in  place  for  the  most efficient   operation   for   both   fuels.      Refer   to   the   mechanical operation  of  the  Gas  On/Off  and  Oil  On/Off  systems  for  specific adjustment details (pages 13 and 15). Gas On/Off System with Oil On/Off Fixed Air Low Fire Start System The  air  dampers  are  adjusted  and  locked  in  place  for  the  most efficient high fire operation for both fuels.  Smooth light off on gas is achieved by the use of a slow opening diaphragm or motorized gas  valve,  which,  once  energized,  allows  gas  flow  to  steadily increase from the initial light off volume up to the high fire volume. Smooth light off on oil is achieved by the use of a solenoid oil valve bypass system which allows a reduced amount of oil to be burned at light off and then switching to the high fire rate once the low fire has  been  established.    Refer  to  the  mechanical  operation  of  the Gas On/Off system and the Oil Fixed Air Low Fire Start system for specific adjustment details (pages 13 and 16). Gas Low/High/Off System with Oil Low/High/Off System For Gas - movable air dampers are adjusted to provide a smooth light off position and then moved to the high fire  position  through mechanical linkage from a motorized gas valve.  The air dampers are adjusted to open to provide maximum combustion efficiency at the  gas  high  fire  input  rate.    For  oil  -  the  same  air  dampers  are operated  by  a  hydraulic  oil  cylinder  which,  through  mechanical linkage, is adjusted to provide a smooth light off and then open to a point where the highest combustion efficiencies will be achieved at the high fire input rate.  Smooth oil light off is further achieved by the  use  of  a  solenoid  oil  valve  bypass  system,  which  allows  a reduced amount of oil to flow at light off and then switches to the high fire rate (simultaneously energizing the hydraulic oil cylinder) once low fire has been established. The mechanical linkage from the gas valve is physically arranged so  that  the  hydraulic  oil  cylinder  (which  is  non-operational  when burning   gas)   has   no   effect   on   the   gas   linkage   adjustments. Similarly, the gas valve (which is non operational when burning oil) has no effect on oil linkage adjustments.  It  should  be  noted  that when   the   hydraulic   oil   cylinder   moves   the   air   dampers,   the movement of the air dampers  will  cause  the  motorized  gas  valve linkage to move up and down with the opening and closing of the hydraulic  oil  cylinder.    The  motorized  gas  valve  linkage  is  “free floating,” and even though it moves with the oil cylinder operation, it  cannot  cause  any  gas  flow  to  pass  through  the  motorized  gas valve.  Refer to the mechanical operation of the Gas Low-High-Off system  and  the  Oil  Low-High-Off  system  for  specific  adjustment details (pages 14, 16, 17 and 18). Note The oil side operation  can  be  supplied  with either   a   Suntec   or   a   Webster   oil   pump. Refer  to   the   mechanical   operation   for   the specific system for adjustment details. Gas Low/High/Low System with Oil Low/High/Low System Refer  to  the  above  explanation  of  Gas  Low/High/Off  System  and Oil  Low/High/Off  System.    The  Gas  Low/High/Low  Systems  are identical  in  operation,  except  that  an  additional  temperature  or pressure control is added to the system, which at a selected preset point  will  electrically  switch  the  motorized  gas  valve  (which  is  a different   model   number   than   the   Low/High/Off   motorized   gas valve) to an adjustable “Low Fire” position.  This low fire position is an  adjustment  that  is  designed  internal  to  the  gas  valve  and, depending  upon  the  specific  manufacturer  of  the  valve,  will  be found either in the valve wiring compartment or under a removable cap on top of the valve.  Refer to the valve manufacturer's product bulletin supplied with the burner for specific details. For  the  Low/High/Low  system,  oil  side  operation  the  additional temperature  or  pressure  control  will  also  cause  the  solenoid  oil valves, hydraulic  oil  cylinder  and  air  dampers  to  go  to  a  “low  fire position”  at  the  same  preset  temperature  or  pressure  as  the  gas side operation.  The oil side low fire position is one and the same position  as  the  light  off  position,  i.e.,  the  air  dampers  and  oil pressures  have  identical  settings  (as  compared  to  the  gas  side  - which  can  be  adjusted,  if  desired,  to  have  different  settings  for “light off” and “low fire”).  Refer to the mechanical operation of the Gas (page 3 - 974)