TM 5-3895-374-24-2 4.  Gas High Fire Input Cannot Be Achieved A. Gas   company   pressure   regulator   or   meter   operating incorrectly, not allowing required gas pressure  at  burner train inlet.  Have gas company correct. B. Gas  cock  upstream  of  train  inlet  not  fully  open.    Check and correct. C. Gas line obstructed.  Check and correct. D. Gas  train  main  and/or  leak  test  cocks  not  fully  open. Check and correct. E. Gas   supply   line   between   gas   company   regulator   and burner inlet too small.  Check supply pressure at meter, determine    pressure    drop    and    increase    line    size    as required,   or   raise   supply   pressure   to   compensate   for small  line.    Do  not  raise  pressure  so  high  that  under static   (no   flow)   conditions   the   pressure   exceeds   the maximum allowable pressure to the gas train components on the burner. F. Burner  gas  train  components  sized  too  small  for  supply pressure.  Increase component size as appropriate. G. Automatic  gas  valve  not  opening  fully  due  to  defective operation.  Replace gas valve. H. Side tee (limiting) orifice (if supplied) too small.  Replace with correct size. I. On  modulating  burner,  butterfly  valve  not  fully  opened. Readjust. J. Defective main gas pressure regulator.  Replace. K. Incorrect spring in main gas pressure regulator.  Replace as required. L. Main gas pressure regulator vent line obstructed.  Check and correct. M. Normally  open  vent  valve  (if  supplied)  not  closing  when automatic gas valves open.  Check to see if valve is fully closed  when  automatic  valves  are  open.    Replace  vent valve, if not closing fully. OIL OPERATION 1.  Burner Motor Runs, but Direct Spark Ignited Oil Flame Is Not Established A. Defective or incorrect size oil nozzle.  Remove and clean or replace. B. Low oil pressure.  Check with gauge for correct “light-off” pressure. C. Defective oil pump.  Replace. D. Defective oil solenoid valve.  Replace. E. Oil pump coupling loose or defective.  Replace or tighten as required. F. Low    oil    pressure    switch    (if    supplied)    defective    or incorrectly set.  Adjust or replace switch. G. Ignition transformer defective.  Replace. H. Ignition  electrode  set  incorrectly.    Remove  electrodes and reset. I. Ignition   electrodes   cracked   and   grounding   out   spark. Replace electrodes. J. Ignition   leadwire   defective   and   grounding   spark   out. Replace. K. Ignition plug in connections at transformer or electrodes loose.  Tighten. L. Air flow switch (if provided) not making.  Reset pressure or replace. M. Defective flame safeguard control or plug in purge timer card.  Replace. N. Air dampers held in high fire position due to mechanical binding of linkage.  Readjust linkage. O. Loose    wiring    connections.        Check    and    tighten    all connections. 2.  Oil Flame ignites, but then Flame Safeguard Control Locks Out on Safety A. Flame scanner lens dirty.  Remove and clean. B. Scanner sight tube blocked or dirty.  Check and clean. C. Flame scanner defective.  Replace. D. Defective oil nozzle causing unstable flame and scanning problems.  Replace oil nozzle. E. Fuel/air  ratios  incorrect,  resulting  in  unstable  or  smoky flame causing scanner flame sighting problem.  Readjust ratios for clean stable flame. F. Defective flame safeguard amplifier or control Replace as appropriate. 3.    Oil  Flame  Extremely  Smoky  at  Light  Off  or  in  Low  Fire Position A. Defective or incorrect size oil nozzle.  Replace. B. Fuel/air ratio incorrect Readjust    C.  N.C.  oil solenoid valve   in   oil   nozzle   return   line   not   opening.      Check electrical circuitry and replace valve if defective. D. On two-step pump - N.O.  pump mounted solenoid valve malfunctioning.  Replace valve or pump. 4.  Light Off Oil Flame Is Established and Proven, but Burner Will Not Attempt to Go to the High Fire Position A. Low/High/Low or Modulating burner high fire temperature or  pressure  control  could  be  defective  or  not  set  to  call for high fire.  Readjust or replace control. B. Loose   wires   or   incorrectly   wired.      Verify   wiring   and tighten all connections. C. Flame safeguard control or high fire panel switching relay (if supplied) defective.  Verify and correct as required. D. High fire 3 way solenoid valve defective.  Replace. E. Hydraulic oil cylinder defective.  Replace. F. On two-step  pump  -  N.O.    solenoid  valve  defective  (not closing).  Replace pump or valve. G. Linkage mechanically binding.  Readjust linkage. H. On   modulating   system   -   defective   modulating   motor. Replace. 5.    Low  Oil  Flame  Is  Established  and  Proven,  but  Flame  Out Occurs in Transition from Low Fire to High Fire A. On Low/High/Off or Low/High/Low system - N.C. oil solenoid valve in nozzle return line not closing (or leaking) Check valve operation and replace if necessary. B. On  two-step  oil  pump  -  N.O.    solenoid  valve  defective (not closing).  Replace valve or pump. C. Defective or incorrect size oil nozzle.  Replace. D. High fire oil pressure too low.  Readjust. E. Air  dampers  set  too  far  open  at  low  fire,  which  causes flame   to   blow   out   in   starting   to   high   fire.      Readjust dampers. F. Oil pump coupling loose or defective.  Tighten or replace. G. Defective oil pump.  Replace. H. Linkage mechanically binding.  Readjust. I. Make certain the #72 orifice into the N.C.  side of the 3 way valve has not been removed. J. On  modulating  systems  -  fuel/air  ratios  set  incorrectly. causing   flame   to   blow   out   when   going   to   high   fire Readjust linkage. (page 3-990)