HI-HEAT position, the remaining heaters are en- ergized,   providing   maximum   heating   capacity ( 12,000 BTUH) . 6-3. Repair Procedures a. If  the  system  must  be  opened  for  repair  or replacement  of  parts,  open  the  suction  service valve and relieve the system pressure. Connect a hose  line  to  the  suction  service  valve  and  purge the  refrigerant  to  an  outside  area. b. After  purging  the  system,  allow  the  tubing to warm to the ambient temperature before open- ing  the  system;  this  delay  will  help  prevent  the formation  of  condensation  on  the  inside  walls  of the tubing. Plug or cap all openings as a part is removed to minimize the entry of dirt and mois- ture. c.  Use  a  silver  solder  on  all  soldered  connec- tions. Easy-Flo silver solder (or equivalent) with a  50  percent  silver  capacity  and  a  melting  point of  approximately  1160°  F  is  recommended.  Con- tinually pass dry nitrogen through the tubing or connections  being  soldered  to  prevent  formation of  harmful  copper  oxides. d. No metal contact on capillary tubes is allow- able; use tape to prevent such contact. 6-4.  Fan   Motor a. On-Equipment Testing.  Before removing the motor  for  replacement,  test  the  motor  windings for any opens, grounds, and resistance tolerances. (1)   Disconnect   electrical   connector   from motor. (2)  Check  for  continuity  across  each  combi- nation of two motor terminals. Lack of continuity indicates an open winding. (3)  Place  one  probe  of  the  continuity  tester against  the  motor  housing  and  the  other  probe against  each  of  ‘the  motor  terminals,  one  at  a time.  If  continuity  is  indicated  between  any  ter- minal and the housing, the motor is defective. (4)  Connect  the  motor  to  a  208V,  3-phase, 60  Hz  power  source.  Use  a  clampon  or  inseries type ammeter and measure the amperage in each of the motor leads. Amperage should be 4.2 amps in each lead. b.  Removal.  Refer  to  paragraph  3-36  and  re- move the motor. c.  Disassembly.  Refer  to  figure  6-2  and  disas- semble the motor. d.  Testing. (1) Overload  protector.  Disconnect  the  elec- trical  leads  from  the  overload  protector  (fig. 6-2).  Test  the  protector  for   continuity;   if   conti- nuity does not exist, replace the overload protec- tor. (2)  Motor  bench  test.  Perform   the   growler tests on the stator as instructed in TM 5-764. Re- place  a  defective  stator. e. Ceaning, Inspection, and Repairs. (1) Clean  all  parts  with  a  cloth  dampened in  approved  cleaning  solvent. (2)   Inspect   stator breaks,  or  other  defects. defective  housing. (3)  Inspect  bearings and  out-of-round.  Replace housing. housing   for   cracks, Replace  a  damaged  or for  pits,  scoring,  wear, a damaged or defective (4)  Inspect  the  rotor  shaft  for  cracks,  wear, or misalinement. Replace a damaged or defective rotor. (5) Inspect the rotor for cracks, breaks, and damaged  laminations.  Replace  damaged  rotor. (6)  Replace  stator  if  it  does  not  meet  test standards (d, above). (7)  Refer  to  TM  5-764  for  motor  repair  in- structions. f. Reassembly.   Refer  to  figure  6-2  and  reas- semble the motor. g. Installation.   Refer  to  paragraph  3-36  and install the fan motor. 6-5. Refrigerant System Servicing Warning:   Avoid   bodily   contact   with   liquid refrigerant   and   avoid   inhaling   refrigerant   gas. Be  especially  careful  that  refrigerant  does  not come  in  contact  with  the  eyes.  In  case  of  refrig- erant   leaks,   ventilate   the   area   immediate   y. a.  Testing  Refrigerant  System  for  Leaks. (1) Halide  torch  leak  detector  method.  The preferred  method  of  testing  for  refrigerant  sys- lem  leaks  is  by  using  a  halide  torch.  The  halide torch exploring tube is passed over all joints, “cou- plings,  and  valves.  A  refrigerant  leak  will  cause the  flame  of  the  torch  to  change  from  blue  to green. If the leak is large, the flame will be dense blue with a reddish tip. A very large leak may ex- tinguish  the  flame.  Mark  all  spots  where  leaks are noticed. Drain the refrigerant system, repair the leak, and pressure test the system. (2)  Soap  solution  method.  While  operating the  air  conditioner,  brush  all  possible  points  of leakage  with  soap  solution  and  watch  for  bub- bles.   Wipe   off   soap   solution   and   mark   leaks. Drain  the  refrigerant  system;  repair  leaks  and pressure test the system. b.  Draining.  Refer to figure  6-3 and  drain  the refrigerant   system. c.  Pressure  Testing  and  Evacuating.  Refer  to figure 6-4 and pressure test and evacuate the re- frigerant system. 6 - 3