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.
(e) Install junction box and control panel assembly in
the air conditioner as
follows: (See Figure 4-2) .
1. Position the assembly in the air conditioner, and secure with six screws (7) and two screws (8) and washers
(9) .
2. Insert cable core into hole in circuit breaker actuator arm (15) . Install core end fitting (14) on cable core, finger
tight.
3. Install hold-down clamp (16) over cable, and secure to top of junction box with two screws and washers.
4. Adjust core end fitting (14) to provide 0.14 - 0.25 inch (3-6 MM) clearance below the actuator arm (15)
when the cable is fully extended and the circuit breaker is off.
5. Connect wiring harness plugs to the junction box and the control panel assembly.
WARNING
Hearing protection must be worn when maintenance is performed while air conditioner is
in operation. 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.
(f) With power connected to the air conditioner, turn the mode selector switch to cool, and turn the temperature con-
trol thermostat to the maximum decrease position. Prop the front access panel across the opening. With the compres-
sor operating, observe the sight-glass liquid indicator. If bubbles or milkiness appear, top off the refrigerant charge as
follows:
1. Connect a cylinder of refrigerant, R22, loosely to the gage port of the suction line service valve, and open the
cylinder shutoff valve for a few seconds to purge air from the line. Tighten the connection. Leave the cylinder upright,
or connect the line to the 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 the liquid in the 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.
5-22. Check Valve.
The check valve (13, Figure 5-2) is located in the upper left corner of the lower compartment, just behind the pressure
relief valve (15) . Functionally, it is just downstream of the condenser coil (1) and prevents pressure in the expansion
section from forcing refrigerant back through the condenser coil when the compressor is in bypass operation.
a. Access. Obtain access to the check valve in accordance with the following directions:
(1) Unscrew four panel fastener screws from the front access panel, and remove the panel.
5-38