TM 9-4120-395-14&P
Section IV. OPERATION UNDER UNUSUAL CONDITIONS
Para.
General ....................................................................................................................................................................... 2-14
Operation in Extreme Heat.......................................................................................................................................... 2-15
Operation in Extreme Cold .......................................................................................................................................... 2-16
Operation in Dusty or Sandy Conditions ...................................................................................................................... 2-17
Operation in Unusually Wet Conditions ....................................................................................................................... 2-18
Operation in Salt Air or Sea Spray .............................................................................................................................. 2-19
Operation Under Emergency Conditions ..................................................................................................................... 2-20
2-14. 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.
2-15. OPERATION IN EXTREME HEAT. The air conditioner is designed to operate in temperatures up to 120 degrees
Fahrenheit (49 degrees Centigrade). Extra care should be taken to minimize the cooling load when operating in 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.
NOTE
Weather stripping, the installation of storm doors and windows (if appropriate), and
insulation of surfaces exposed to the outside are recommended when operating in higher
temperatures for extended periods.
2-16. OPERATION IN EXTREME COLD. Extra care should be
taken to
minimize the heating load when operating in
lower 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.
NOTE
Weather stripping, the installation of storm doors and windows (if appropriate), and insulation
of surfaces exposed to the outside are recommended when operating in lower temperatures
for extended periods.
2-17. OPERATION IN DUSTY OR SANDY CONDITIONS. Dusty and sandy conditions can seriously reduce the
efficiency of the air conditioner by clogging the air filter 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 drain pan and water drain line. Some of the steps that may be
taken are:
a.
Frequent cleaning of filter and cleaning all other areas of dust and sand accumulation. In extreme
conditions, daily replacement of the filter may be necessary.
b.
Contact unit maintenance to adjust the fresh air damper to limit the amount of dusty or sandy outside air
entering the system.
2-18. OPERATION IN UNUSUALLY WET CONDITIONS. The air conditioner is designed for normal exposure to the
elements, so it is reasonably waterproof. However, in an extremely wet climate, more frequent inspection and cleaning
of the drain pan and drain line may be required to insure proper drainage and prevent accumulation of water inside the
cabinet.
2-8