TM  5-4120-361-14 (9) Nameplate. It is located on the left side of facturer’s  name,  the  air  conditioner  serial  and  model the air conditioner near the front, and contains the manu– numbers  and  other  pertinent  nameplate  data. Section  IV.  OPERATION  UNDER  UNUSUAL  CONDITIONS 2-16. Operation in Extreme Cold. a. General. The air conditioner is designed to operate on the heating cycle in ambient temperatures as low as minus 50°F (-45°C) and on cooling cycle with 0°F (-18°C) air entering the condenser and 70°F (21°C) air entering   the   evaporator. b.  Before  Operation.  Before  starting  on  cooling cycle  be  sure  cover  is  removed  from  condenser  air  intake  and discharge.  Clear  all  ice  and  snow  from  openings.  Be  sure  all dampers are in operating condition. c. After  Operation.  Install  cover  over  condenser air intake and discharge openings. 2-17. Do not disturb wiring during cold weather unless absolutely necessary. Cold temperatures  make  wiring  and  insulation brittle and easily broken. Operation in Extreme Heat. NOTE Unit Preventive Maintenance Checks and Services (PMCS) should be performed at daily   intervals. a. General. The air conditioner is designed to operate in temperatures up to 120°F (49°C). Extra care should be taken to minimize the cooling load when operating in  extreme  high  temperatures. b.  Protection. (1) Check all openings in the enclosure, especially doors and windows, to be sure they are tightly closed. Limit in and out traffic if possible. (2)  When  appropriate,  use  shades  or  awnings to shut out direct rays of the sun. (3) When possible, limit the use of electric lights and other heat producing equipment. (4) Limit the amount of hot, outside air introduced through the fresh air damper to that essential for ventilation. 2-16 Change  3 NOTE Weatherstripping, the  installation  of storm  doors,  and  windows,  if  appropriate, and insulation of surfaces exposed to the outside  is  recommended  when  operating in extremely high temperatures for extended  periods. c.  Cleaning. (1)  Clean  outside  grilles,  coils,  filters,  and mist eliminator more frequently. 2-18. Operation  in  Dusty  or  Sandy  Areas. NOTE Unit Preventive Maintenance Checks and Services (PMCS) should be performed at daily   intervals. a.  General.  Dusty  and  sandy  conditions  can seriously reduce the efficiency of the air conditioner by clogging the air filter, mist eliminator, and coils. This will cause a restriction in the volume of airflow. Accumulation of dust or sand in the condenser coil and/or in the compressor compartment may cause overheating of the refrigeration system. Dust or sand may also clog the condensate trap and water drain lines. Never operate the air conditioner without having  the  air  filters  in  place. b. Protection. (1)  Shield  the  air  conditioner  from  dust  as much  as  possible. (2) Take advantage of any natural barriers which  offer  protection. (3) Limit the amount of dusty or sandy outside  air  introduced  through  the  fresh  air  damper. (4) Roll down and secure the fabric cover on the back of the cabinet during periods of shutdown. c. Cleaning. (1) Keep the air possible. (2)  Pay  particular grilles,  condenser,  filters,  mist electrical  components. conditioner as clean as attention  to  the  outside eliminator,  louvers,  and (3) In extreme conditions, daily cleaning of condenser,  filters,  and  outside  grilles  may  be  necessary. 2-19. Operation Under Rainy or Humid Conditions.