Section IV OPERATION UNDER UNUSUAL CONDITIONS

TM 5-4120-393-14

2-16. General . 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 prevent undue loading and excessive

wear on the equipment.

2-17. Operation In Extreme Heat. The air conditioner is designed to operate in temperatures up to 120F(49 C). Extra

care should be taken to minimize the cooling load when operating in extremely high temperatures. Some of the steps that

may be taken are:

a. Check all openings in the shelter or enclosure, especially doors and windows, to be sure they are tightly closed.

Limit in and out traffic, if possible.

b. When possible, use shades or awnings to shut out direct rays of the sun.

c. Limit the use of electric lights and other heat producing equipment.

d. Limit the amount of hot, outside air introduced through the fresh air damper to that needed for ventilation.

NOTE

Weather stripping, 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 is anticipated.

2-18. Operation In Extreme Cold. The air conditioner is designed to operate in temperatures down to 50F (45C).

Extra care should be taken to minimize the heating load when operating in extremely low temperatures. Some of the

steps that may be taken are:

CAUTION

Do not disturb electrical -wiring that has been exposed to extremely low

temperatures. Both the wire and insulation become brittle when cold and are

easily broken.

a. Check all openings in the enclosure, especially doors and windows, to be sure they are tightly closed. Limit in

and out traffic, if possible.

b. Open shades and awnings to permit entry of direct rays of the sun, if appropriate.

c. Limit the amount of cold, outside air introduced through the fresh air damper to that needed for ventilation.

NOTE

Weather stripping, the installation of storm doors and windows (if appropriate),

and insulation of surfaces exposed to the outside is recommended when operating

in extremely low temperatures for extended periods is anticipated.

2-19. Operation In Dusty Or Sandy Conditions. Dusty and sandy conditions can seriously reduce the efficiency of the

air conditioner by clogging the air filters and thereby causing a restriction of 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 mist eliminator, condensate trap, and water drain lines Some of the steps that may be

taken are:

a. Frequent cleaning of filters and all other areas of dust and sand accumulation.

In extreme conditions, daily

cleaning of filters may be necessary.

2-17