Freezer Frame-Drain Heater,Hot Gas Repl.(611, 511)
  611     Use Prior to Serial #1810000.
  511     Use Starting with #M1004775 and between
          #M964470-M964769. Prior to #M1004775
          except between #M964470-M964769 see
          4201080. If just the drain pan & pan
          heater are needed see 4201000