TM9-4120-400-14
2-12. OPERATION IN EXTREME COLD. - contined
NOTE
Weather stripping, the installation of storm doors, and windows, if appropriate, and
insulation of surfaces exposed to the outside is recommended when operation at
extremely low temperatures for extended periods is anticipated.
d. Before attempting to start the unit in the COOL mode or when fresh air is being used during the HEAT
mode, be sure that cover is rolled up and all exposed air openings are clear of ice and snow.
e. When the unit is to be used at low temperatures in the COOL mode, the low refrigerant pressure cutout
switch must be jumped. Notify supervisor.
f. Be sure that all dampers are operating freely.
g. If unit is not being used or is being used in the HEAT mode without fresh air, close (roll down) and secure
the fabric cover.
2-13. OPERATION IN DUSTY OR SANDY
CONDITIONS.
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. Some of the steps that may be taken are:
a. Frequent cleaning of filters, mist eliminator, coils and all other areas of dust and sand accumulation. In
extreme conditions, daily cleaning of filters may be necessary.
b. Limit the amount of dusty or sandy outside air introduced through the fresh air damper to that essential for
ventilation.
C.
Roll down and secure the fabric cover on the back of the cabinet during periods of shutdown.
2-14. OPERATION IN
UNUSUALLY WET
CONDITIONS.
The air conditioner is designed for normal exposure to the elements, so it is reasonably waterproof. Some of the
steps that should be taken in an extremely wet climate are:
a. More frequent inspection and cleaning of the mist eliminator, condensate trap, and drain lines to insure
proper drainage and prevent accumulation of water inside the cabinet.
b. Roll down and secure the fabric cover on the back of the cabinet during periods of wet, windy weather
when the air conditioner is not in operation.
c. Roll up and secure the fabric cover during dry weather when the air conditioner is not in operation so that
the interior can dry out and condensation will not accumulate.
2-14