Section IV. OPERATING OF EQUIPMENT

TM 5-4120-273-15

Section IV. OPERATING OF EQUIPMENT

(3) Ventilating operation.

2-11. General

(a) Place selector switch in ventilate posi-

a. The instructions in this section are published

tion.

for the information and guidance of personnel re-

(b) Place fan speed toggle switch in de-

sponsible for operation of the air conditioner.

sired position.

b. The operator must know how to perform

every operation of which the air conditioner is

door and close intake grille damper.

capable. This section gives instructions on start-

ing, stopping and operating details of the air con-

Caution: If during operation of the

ditioner. Since nearly every application presents a

unit the fan motor stops because of a locked

different problem, the operator may have to vary

rotor condition, shut off unit immediately. Do

given procedure to fit the individual job.

not try to restart for at least ten minutes. See

paragraph 3-24 for inspection and testing.

2-12. Starting

Note. If the air conditioner fails to start, open

front access panel and push reset control on circuit

a. Preparation for Starting.

breaker (fig. 2-2).

(1) Perform necessary daily preventive

maintenance services (para 3-6).

2-13. Stopping

(2) Check electrical requirements (para 2-

Refer to figure 23. Place selector switch in

5d).

"OFF" position.

b. Starting.

(1) Cooling operation.

2-14. Operation Under Usual Conditions

(a) Position thermostat for desired tem-

a. Refer to paragraph 212 and start the air

perature.

conditioner.

(b) Place fan speed toggle switch in de-

b. Refer to figure 2-3, and operate the air con-

sired position.

ditioner.

2-15. Operation in Extreme Cold

(d) For cooling with 100 percent recircu-

lated air, close damper door.

a. General. The air conditioner is designed to

operate at a minimum low temperature of 50F.

(e) For cooling with fresh makeup air,

ambient. Be sure that all thermostatic controls and

open damper door and partially close intake

dampers are in working order.

grille damper.

b. Electrical System. Make sure the electrical

(f) For cooling with fresh makeup air

system is free of ice and moisture.

drawn through chemical biological filter unit

when outdoor air is contaminated, close damper

Caution: Do not disturb the wiring during

door and partially close intake grille damper.

cold weather unless absolutely necessary. Cold

(2) Heating operation.

temperatures make wiring and insulation brit-

tle and are easily broken.

(a) Position thermostat for desired tem-

perature.

2-16. Operation in Extreme Heat

(b) Place fan speed toggle switch in de-

a. General. The air conditioner is designed to

sired position.

operate satisfactorily at temperatures up to

120F.

hi-heat position.

b. Ventilation. Allow sufficient room around

(d) For heating with 100 percent recircu-

the air conditioner for adequate air circulation.

lated air, close damper door and open intake grille

Note. Do not restrict the flow of air at the intake

damper.

and discharge openings of the unit.

(e) For heating with fresh makeup air,

2-17. Operation in Dusty or Sandy Areas

open damper door and partially close "intake grille

damper.

Clean the condenser coil (para 3-5c) and evapora-

tor coil (para 3-55c) weekly or more often if nec-

(f) For heating with fresh makeup air

essary. Clean the air conditioning filter (para 3-

drawn through chemical biological filter unit

when outdoor air is contaminated, close damper

9b), fresh air inlet screen and condenser screen

(para 3-20) daily.

door and partially close intake grille damper.

2-7