The air conditioner is designed to operate normally within a wide range of climatic conditions. However, some extreme
conditions require special operating and servicing procedures to maintain high efficiency and to prevent undue strain or
wear of the equipment.
2.9. Operation in Extreme Heat
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 120F (49C). Extra care should be
taken to minimize the cooling load when operating in extreme high temperatures.
(1) Check all openings in the enclosure. especially doors and windows, tobe 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.
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 peri-
c. Cleaning. Clean outside grilles, coils, filters and mist eliminator more frequently.
2.10. Operation in Extreme Cold
The air conditioner is designed to operate in temperatures as low as -50F (-45C). At extremely low temperatures. extra
care should be taken to reduce heat loss of the enclosure, by weather-stripping windows and doors, insulating surfaces
exposed to the outside, and limiting the amount of outside air drawn in through the fresh air vent of the air conditioner. Do not
disturb wiring during extremely cold weather. Wire and insulation become brittle, and are easily broken.
2.11. Operation in Dusty or Sandy Conditions
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.