Control, Ref 500 Series Svce (501R, 511, 532, 542,
          550, 561)
  501R    Use Starting with #M821354/P612141.
          Prior to #M821354/P612141 see 4200930.
  511     Use Regardless of Serial Number.
  532     Use Starting with #M821354/P612141.
          Prior to #M821354/P612141 see 4200930.
  NOTE:   If Ref Fan Blade is Grey, Replace with
          White Blade 7014696
  542     Use Regardless of Serial Number.
  550     Use Starting with #M821354/P612141.
          Prior to #M821354/P612141 see 4200930.
  561     Use Starting with #M821354/P612141.
          Prior to #M821354/P612141 see 4200930.