TM 9-4120-357-14
2. Weigh the cylinder, and record the weight.
3. Open the discharge line service valve, and slightly open the refrigerant cylinder shutoff valve. Liquid refriger-
ant will be sucked into the refrigeration system rapidly at first, then more slowly as pressures begin to equalize. When
25 pounds (11.4 KG) of refrigerant have flowed into the refrigeration system, as indicated by the scale, close the dis-
charge line service valve and the cylinder shutoff valve.
(6) Install the junction box to permit an operational check of the air conditioner. Proceed with the following steps:
(a) Place the junction box and control panel assembly in position in the unit, and secure with six screws (7, Fig-
ure 4-3) through the casing into the mounting flange, and two screws (8) and washers (9) through the mounting
bracket.
(b) Insert the end of the flexible cable core through the hole in the top of the circuit breaker actuator arm (15) ,
and slide the core end fitting (14) onto the cable. Tighten the setscrew finger tight. Install the cable hold-down clamp
(16) over the cable, and secure it to the upper right side of the junction box with two screws and lock washers. Adjust
the core end fitting (14) to provide 0.12 - 0.25 inch (3-6 MM) clearance under hole in actuator arm (15) when cable is
fully extended and circuit breaker is off. Tighten the setscrew.
(c) Connect all wiring harness plugs to
their corresponding receptacles on
the junction box and control panel as-
sembly. Drop front access panel across opening temporarily. Connect power to the air conditioner.
(7) Check operation, and top off refrigerant if necessary, as follows:
WARNING
Hearing protection must be worn when maintenance is performed while air conditioner is in op-
eration. Failure to heed this warning can result in hearing loss or injury.
CAUTION
Connect power to unit as soon as possible after charging or any period when power has
been disconnected. Allow heater time to vaporize refrigerant in compressor before opera-
tion in COOL mode. If knocking or pounding is heard at start of COOL mode, turn selec-
tor switch to OFF or VENTILATE at once and allow additional warm up time.
(a) With power connected to the air conditioner, turn the mode selector switch to cool, and turn the temperature
control thermostat to maximum decrease position. With the compressor operating, observe the sight-glass liquid indi-
cator. If bubbles or milkiness appear, top off the refrigerant charge as follows:
1. Connect a cylinder or refrigerant, R22, loosely to the gage port of the suction line service valve. Open
the cylinder shutoff valve for a few seconds to purge air from the line. Tighten the connection. Leave the cylinder up-
right, or connect line to vapor valve.
2.
With the air conditioner compressor operating, open the suction line service valve and the cylinder shutoff
valve to charge refrigerant gas into the system while observing the sight-glass liquid indicator.
3. When liquid in sight-glass indicator runs clear and free of bubbles, close the suction line service valve and
the cylinder shutoff valve.
4. Disconnect the refrigerant cylinder. Replace caps on both service valves.
g. Final Assembly. Replace the front access panel on the air conditioner by inserting lower edge of panel behind
step in base plate, and pushing into contact with casing. Secure with four panel fastener screws.
5-20. Pressure Regulating Valve.
a. Access. Remove panels and grilles to obtain access to the pressure regulating valve (V2) and the system service
valves as follows:
(1) Remove the circuit breaker access cover from the front access panel by turning the four camlock fasteners a
quarter-turn counterclockwise.
(2) Unscrew four panel fastener screws from the front access panel. Remove the panel.
(3) Remove 12
screws and washers from each evaporator intake grille. Remove the two grilles.
5-32