TM 9-4940-342-14&P (5)  When   proper   tension   is   achieved   secure mounting    bolts,    nuts    and    align    pulleys    while tightening. (6)  Rotate  belt  by  hand  to  check  for  unusual drag   or   binding   and   reinstall   back   access   panel, securing with mounting screws. 4-18.  Oil Pump Assembly (Refer to Fig C-11) a.  Periodically  it  is  advisable  to  remove  the  oil pump filter screen and clean with solvent to remove all foreign matter. b.  To  remove  oil  pump  filter  screen,  proceed  as follows: (1)  Remove the eight cover mounting bolts and separate cover from body, exposing filter screen. (2)  Remove filter screen and clean. (3)  Reinstall   screen   and   secure   cover   with eight locating bolts. 4-19.  Burner Adjustment and Cleaning (Refer to Fig C-16) a.  The burner plate assembly may be removed by disconnecting  the  two  spark  electrode  leads,  intake copper  tube  lines,  flame  scanner  and  three  wing nuts. b.  Gently   lower   assembly   from   blower   duct being careful not to drop or bump spark electrodes. c.  Wipe  off  complete  assembly  and  remove  the two burner nozzles for disassembly and cleaning of external screens. d.  Reinstall nozzles and proceed to inspect spark electrodes   for   cracks,   pits   or   signs   of   arcing   to burner plate. e.  If electrode replacement is not required adjust to  specifications  as  referenced  and  reinstall  burner assembly. f.   Prior  to  connecting  flame  scanner  wipe  off lens with clean rag and secure finger tight only. 4-20.  Fuel Nozzles-Removal and Cleaning (Refer to Fig C-16) a.  The   burner   assembly   consists   of   two   fuel nozzles,  each  nozzle  consisting  of  a  filter  screen stem, spinner core and body with orifice. b.  To  remove  and  clean  fuel  nozzles  proceed  as follows: (1)  Fuel    nozzles    should    be    removed    and cleaned every three or four months or after each 250 hours   of   unit   operation.   If   fuel   is   contaminated, greater frequency may be required. (2)  Remove burner assembly, see paragraph 4- 19 and remove nozzles utilizing two wrenches. (3)  Remove nozzle screen and spinner core and clean in solvent, blowing down with air pressure. 4-21.  Coil Inlet Assembly (Refer to Fig C-14) The    coil    inlet    plumbing    assembly    should    be inspected  for  leaks,  loose  fittings  and  connections. Should  inspection  reveal  any  problems,  repair  per instructions   in   paragraph   4-10,   loose   or   leaking connections. 4-22.  Coil Outlet Assembly (Refer to Fig C-17) a.  The  cod  outlet  plumbing  assembly  should  be inspected  for  leaks,  loose  fittings  and  connectors and repaired per paragraph 4-10. b.  A  leaking  discharge  or  soap  tank  fill  valve may   be   repaired   by   loosening   valve   bonnet   and removing stem assembly. c.  Valve seat, teflon disk, may be turned over to utilize the new surface. d.  Leaks around the stem packing gland cap may be  corrected  by  tightening  the  packing  gland  nut when the valve is in a partially open position. 4-23.  Preheat Coil Assembly (Refer to Fig C-18) a.  Inspect  preheat  coil  assembly  for  excessive corrosion on support straps. b.  Clean surface and repaint, if necessary. 4-24.  Generating Coil (Inner) (Refer to Fig C-18) a.  Inspect    generating    coil    (inner)    for    leaks, broken    or    cracked    welds    and    any    excessive vibration.  Should  inspection  reveal  any  problems use standard welding procedures for repair. b.  Inspect   coil   for   excessive   soot   buildup   or restrictions  which  may  prevent  normal  venting  of combustion    chamber.    When    the    findings    are confirmed or questionable, it is advisable to request assistance from the next higher level of maintenance to further determine method of corrections. 4-25.  Draining Soap Tank (Refer to Fig C-31) Soap   tank   draining   is   accomplished   by   opening drain   valve   and   flushing   hardened   soap   deposits which may have accumulated on tank bottom. Soap tank stir and fill valve and soap control valve should be closed so deposits do not enter plumbing system. 4-26.  Flame  Safeguard  Control  (Refer  to  Figs 4-1 and 4-2) a.  To aid in troubleshooting the flame safeguard control,   the   following   functional   description   is provided. (1)  When the main disconnect switch is closed, 220V  to  110V  stepdown  transformer  is  powered providing 110V AC to the control circuitry. (2)  Power    from    the    X1    terminal    of    the transformer  secondary  flows  through  circuit  No.  1, protective fuse, normally closed excess 20