Section IV OPERATION UNDER UNUSUAL CONDITIONS

TM 5-4120-386-14

Section IV OPERATION UNDER UNUSUAL CONDITIONS

NOTE

The air conditioner can be equipped for operation in chemical biological

radiological (CBR) environment by connecting filtering equipment to the

rectangular covered opening at the lower left side of the rear surface of

the unit.

2-11. OPERATION IN EXTREME COLD.

General. The air conditioner is designed to operate on the heating cycle in ambient

temperatures as low as -50oF (-45oC) and on cooling cycle with 0oF (-18oC) air

entering the condenser and 70oF (21oC) air entering the evaporator.

Do not disturb wiring during cold weather unless absolutely necessary. Cold

temperatures make wiring and insulation brittle and easily broken.

To start unit in cool mode at 0oF (-18oC) ambient, have organizational

maintenance personnel jumper Low Pressure Cut-Out (LPCO) switch (S-5).

Before Operation. Before starting on cooling cycle be sure fabric cover is rolled up

and secured. Clear all ice and snow from openings. Be sure all dampers are in operating

condition.

After Operation. Roll down and snap on fabric cover over condenser intake and

outlet.

2-12. OPERATION IN EXTREME HEAT.

General. The air conditioner is designed to operate satisfactorily at temperatures

up to 125F (520 C). If unit is operated at condenser inlet temperatures higher than

1 2 5oF (52C), the cooling capacity will be lowered and long periods of operation at

extended temperatures may cause compressor or condenser fan motor to overheat and trip

their internal overload switches or the high pressure cutout switch to shut the unit off.

Filters. To maintain the highest capacity of the unit, the evaporator inlet filter

and fresh air screen should be cleaned weekly or more often if necessary. Dirty filters

reduce the flow of air across the evaporator coil, thereby reducing the capacity of the air

conditioner.

Guards and Louvers. Keep all guards and louvers clean and free of any obstructions

to maintain full air flow through the air conditioner.

Coils. Clean evaporator and condenser coils as frequently as necessary to prevent

dirt or other matter from obstructing the air flow.