Section II. OPERATION UNDER UNUSUAL CONDITIONS

TM 5-4120-374-13

Section II. OPERATION UNDER UNUSUAL CONDITIONS

2-7.

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 120 F (49 C). Extra care should

be taken to minimize the cooling load when operating in extreme high temperatures.

b. Protection.

(1) Check all openings in the enclosure, especially doors and windows, to be 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

periods.

Cleaning.

(1) Clean outside grilles, coils, filters, and mist eliminator more frequently.

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.

CAUTION

Never operate the air conditioner without having the air filters in place.

b. Protection.

(1) Shield the air conditioner from dust as much as possible.

(2) Take advantage of any natural barriers which offer protection.

(3) Limit the amount of dusty or sandy outside air introduced through the fresh air damper.

(4) Roll down and secure the fabric cover on the back of the cabinet during periods of shutdown.

c. C l e a n i n g

(1) Keep the air conditioner as clean as possible.

(2) Pay particular attention to the outside grilles, condenser, filters, mist eliminator, louvers, and electrical

components.

(3) In extreme conditions, daily cleaning of condenser, filters, and outside grilles maybe necessary.

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