ARMY TM 9-4120-380-14
AIR FORCE TO 35E9-136-21
Section IV. OPERATION UNDER UNUSUAL CONDITIONS
2.15 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 in the equipment.
2.16 OPERATION IN EXTREME HEAT. The air conditioner is designed to operate in temperatures up to 125
(52 ). Extra care should be taken to minimize the cooling load when operating m extremely high temperatures. Some
of the steps that may be taken are:
Weather stripping, the installation of storm doors and windows (if appropriate),
and insulation of surfaces exposed to the outside are recommended when
operating in extremely high temperatures for extended periods is anticipated.
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.
2.17. OPERATIONAL EXTREME COLD. The air conditioner is designed to operate with return air temperatures
down to 40 (4.4 ). Extra care should be taken to minimizing the cooling load when operating in extremely low
temperatures. Some of the steps that may be taken are:
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.
Before operating the air conditioner, ensure that MODE SELECT switch is
in the OFF position and that AC power has been applied to air conditioner
for at least 30 minutes (can take up to 24 hours). This is so that the
is necessary to remove all liquid refrigerant from the crankcase, thereby
eliminating the possibility of damage during starting operations at low
If compressor begins to slug, turn MODE SELECT switch to OFF, wait a
few minutes, then turn MODE SELECT switch to COOL position. Turning
the MODE SELECT switch to OFF then to COOL mode prevents the
compressor from slugging, thereby eliminating the possibility of damage
during starting operations at low ambient temperatures.