TM 9-4120-357-14
3. Open the discharge line service valve, and slightly open the refrigerant cylinder shutoff valve. Liquid re-
frigerant 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
discharge line service valve and the cylinder shutoff valve.
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.
(e) With power connected to the air conditioner, turn the mode selector switch to cool, and turn the temperature
control thermostat to the maximum decrease position. Temporarily prop the front access panel across the opening. With
compressor operating, observe the sight-glass liquid indicator. If bubbles or milkiness appear top off the refrigeration
charge as follows:
1. Connect a cylinder of refrigerant, R22, loosely to the gage port of the suction line service 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, and replace caps on both service valves.
g. Final Assembly. Place the front access panel in position, with the lower edge behind the step of the base plate,
and push into contact with the casing. Secure with four panel fastener screws.
5-24. Receiver.
The receiver (11, Figure 5-2) is a small tank, located just behind the drier-strainer (8) and mounted on the wall of the
casing with two band clamps (10) . Functionally, the receiver is located between the condensing and subcooling coils of
the condenser (1) .
a. Access. Obtain access to the receiver as indicated in the following instructions:
(1) Unscrew four panel fastener screws from the front access panel, and remove the panel.
WARNING
Disconnect power input cable from the air conditioner before doing maintenance work on
the unit.
(2) Disconnect all wiring harness plugs from their receptacles on the junction box and control panel assemblies.
(3) Disconnect the circuit breaker operating flexible cable from the junction box as follows:
(a) Loosen the setscrew in the end of the core end fitting (14, Figure 4-3) and slide the end fitting off of the cable
core.
(b) Remove two screws and washers from the cable hold-down clamp (16) , and pull the end of the cable out of
the hole in actuator arm (15) . Tie or tape the cable out of the way
(4) Remove six screws (7) from the casing and mounting flange of the junction box, and remove two screws (8)
and washers (9) from the mounting bracket. Remove the junction box from the unit.
b. Discharging the System. Whenever a refrigeration component must be replaced, you must discharge all gas
from the refrigeration system in accordance with paragraph 5-6.
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