TM 9-4120-357-14
c. Removal. Remove the receiver from the air conditioner in accordance with the following directions:
(1) Remove a screw, two flat washers and a nut from each of the two band clamps (10, Figure 5-2) holding the
receiver (11) to the wall of the casing.
(2) Connect a cylinder of dry nitrogen to the discharge service valve, and establish a flow of 1-2 CFM (0.5 - 1
M3) through the refrigeration system.
(3) Debraze connections to the receiver, making sure to remove bushings (12) as well as tubing connections.
(4) Remove receiver (11) from the air conditioner, and retain band clamps (10) and other attaching hardware
for re-use.
d. Installation. With nitrogen flowing through the system, attach two band clamps to the receiver and connect
tubing and bushing (12) . Braze in place. Secure band clamps (10) to the air conditioner with a screw, two washers and
a nut in each clamp.
e. Purging the System.
CAUTION
Whenever the refrigeration system has been opened to the atmosphere, you must install
a new drier-strainer (dehydrator) before purging and recharging the system.
With the refrigeration system discharged and a hose attached to the gage-port of the suction service valve, connect a
cylinder of oil-pumped dry nitrogen to the gage port of the high-pressure service valve. Open the high-pressure service
valve, and crack open the cylinder shutoff valve to establish a flow of 1-2 CFM (0.5 - 1 M3) through the system. Purge
for at least 30 minutes to expel all other gases, impurities and water vapor. Turn off both service valves before discon-
necting the nitrogen cylinder and the discharge hose.
f. Charging the System. Prepare the refrigeration system for charging by attaching a pressure gage to the high-
pressure service valve gage port, and a pressure hose and drier-strainer, loosely, to the suction service valve gage
port. Leave both valves closed. Proceed as follows:
WARNING
Avoid contact with liquid refrigerant or escaping refrigerant gas. Irreversible tissue dam-
age can result from sudden freezing. Be extra careful to protect the eyes. Do not inhale
high concentrations of refrigerant gas. Keep gas from coming into direct contact with
flame or hot metal surfaces; lethal phosgene gas can be formed.
(1) Connect a cylinder of refrigerant, R22, to the pressure hoses. Open the cylinder shutoff valve slightly to purge
the hose of air, then tighten the hose connection to the suction service valve gage port.
(2) Open both service valves and the cylinder shutoff valve, and charge the system with gas until the gage on the
discharge (high-pressure) service valve registers 70 PSI (5 KG/CM2) . Close the suction service valve and the cylinder
shutoff valve.
(3) Transfer the charging line to the cylinder of dry nitrogen. Open the cylinder shutoff valve and suction service
valve, and let nitrogen flow into the refrigeration system until the discharge pressure gage reads 350 PSI (21.44
KG/CM2) . Close the suction and discharge service valves and the cylinder shutoff valve. Disconnect the charging line
from the suction service valve.
(4) Test the refrigeration system for leaks, using an electronic leak detector, Halide torch or soap bubble method.
The electronic leak detector is preferred. Use GE type H-10 electronic leak detector or equivalent.
CAUTION
The electronic leak detector and the Halide torch are sensitive to the presence of refriger-
ant gas in the atmosphere. When refrigerant gas is present in the atmosphere of the work
area, false indications can result. Use in a well ventilated but draft-free area.
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