TM 9-4940-342-14&P 4-27.  Fuel     Control     Valve     (Thermostat     Ad- justment) (Refer to Fig 2-1) a.  All  units  have  been  tested  at  the  factory  and operated on the various operational modes. Temperature  valves  are  given  in  chapter  2  of  this manual  and  fuel  control  valve  adjustment  will  be required  for  proper  settings.  While  this  control  is extremely reliable,  it can be damaged by dirty fuels (abrasion), water in fuel (corrosion), and deposits on thermal tube assembly (scale). If scaling is suspected, the cleaner should be checked for back pressure (see paragraph 4-9, coil back pressure test). b.  Except for visual checking for scale deposits on the    thermal    tube    and    replacement    of    complete control, it is not necessary to remove the fuel control valve to clean or replace O-ring seals or seat disk. c.  Thermostat should be adjusted by using a small screwdriver  and  placing  blade  into  slotted  stem  on thermostat.   Turn   from   left   to   right   to   decrease temperature,  right  to  left  to  increase  temperature. Make  small  adjustments  1/8  turn  or  less  and  allow for  temperature  to  restabilize  before  making  added adjustment. CAUTION Do  not  attempt  to  regulate  discharge  temperature by altering fuel pump pressure, nor restricting fuel oil  flow  at  burner  ON-OFF  valve.  Control  with fuel control valve only. NOTE The thermostat is very sensitive and care must be used not to bend, drop, bump or over adjust it. 4-28.  Float Valve Adjustment (Refer to Fig C-6) The  float  valve  should  be  set  to  maintain  a  water level   of   approximately   one   to   two   inches   below overflow tube. To adjust, loosen wing screw on float valve rachet arm and move to next notch, according to water level required. If notch relocates too high or too low, gently bend float ball rod arm until desired setting is acquired. 4-29.  Soap Metering Valve Adjustment (Refer to Fig C-4) Soap is introduced into the pumping system through the    pump    intake    check    valve    and    strength    is controlled  by  the  soap  control  valve.  For  a  stronger or   weaker   soap   selection   at   cleaning   gun(s)   turn valve handle counterclockwise to increase amount of soap, clockwise to decrease amount of soap. 4-30.  Pressure  Regulator  Adjustment  (Refer  to Fig C-8 and C-13) a.  The pressure regulator is utilized as a backup control  to  the  excess  pressure  switch,  so  in  the event  of  coil  blockage  all  water  is  bypassed  from the water pump. b.  Adjust the pressure regulator as follows: WARNING Disconnect  main  power  to  unit  before  jumping pressure   switch   contacts   and   removing   jumper after setting regulator. NOTE The  terminal  on  the  excess  pressure  switch  will have  to  be  jumped  or  range  increased  above  370 psi while setting pressure regulator. Set regulator, then reset excess pressure switch. (1)   To  adjust  regulator,  loosen  adjusting  bolt nut and turn bolt clockwise to increase pressure and counterclockwise to decrease the pressure. The hex nut  locks  adjustment  bolt  to  prevent  any  rotation during operation. (2)   The  pressure  setting  should  be  made  as follows: (a)  Back adjusting bolt out to relieve spring tension. (b)  Start  and  run  the  cleaner  at  the  desired pressure and temperature. (c)  Close the discharge valves. (d)  Adjust the regulator to 370 psi relieving pressure   per   preceding   instructions   and   secure adjusting locknut. (e)  Open   cleaning   gun   discharge   valves, and reset excess pressure switch to 350 psi setting and remove jumper wires. 4-31.  Air Blower Adjustment (Refer to Fig C-4) a.  The cleaner is equipped with a closed, forced draft oil burner system and is adjustable by opening and closing air gate. b.  With   cleaner   in   full   operation   as   a   steam cleaner, loosen clamping screws on sliding air gate and adjust accordingly. c.  Slide   air   gate   to   close   opening   until   dark smoke  appears  at  heater  shell  hat  opening.  Slowly open air gate until smoke clears. NOTE A slight haze is acceptable to excessive cleandraft exhaust discharge. d.  Tighten  clamping  screws  on  sliding  air  gate being careful not to move air gate from established position. NOTE If adjustment of air gate fails to correct excessive smoking,  check  air  blower  fan.  If  dirty,  remove and  clean.  Also,  check  for  excessively  worn  or dirty burner nozzles. Check for proper type of fuel. 23