TM 9-4120-357-14
(2) Obtain access to the liquid line solenoid valve by unscrewing four panel fastener screws from the front access
panel, and removing the panel.
WARNING
Disconnect power input cable from the air conditioner before doing
maintenance work on the unit. The voltage used can be lethal.
b. Removal. Before removing the solenoid valve(s), you must discharge all refrigerant in accordance with para-
graph 5-6. After all refrigerant has been discharged from the system, connect a cylinder of dry nitrogen to the discharge
line service valves, open the suction line service valve completely, and establish a flow of dry nitrogen through the sys-
tem at 1-2 CFM (0.5 - 1 M3) for 3-5 minutes to purge all refrigerant, then disassemble the operating parts from the valve
body and remove as follows: (See Figure 4-13.)
(1) Disconnect the wiring harness from the receptacle on the valve coil housing.
(2) Remove the nut and data plate from top of coil housing and lift off the housing and coil from other tube and
plunger assembly.
(3) Remove the two body screws that secure the tube and plunger assembly to the body. Lift off the tube and
plunger assembly, O-ring and diaphragm.
(4) With dry nitrogen flowing through the system, debraze the valve body from the piping on each side.
c. Installation. Install the solenoid valve as indicated in the following procedure:
CAUTION
Make certain that the direction-of-flow arrow on the valve body is
pointing in the proper direction before brazing.
(1) With the replacement solenoid valve disassembled, install the valve body in position, start the flow of dry ni-
trogen through the system and braze connections.
(2) Place the diaphragm in the body, with the pilot port extension up. Install O-ring in recess in tube and plunger
assembly, and lower the tube and plunger assembly onto the valve body. Secure with two body screws, and tighten uni-
formly.
(3) Install the coil and housing assembly over the enclosing tube, as shown in Figure 4-13. Place the data plate
on top of the housing, and secure the assembly with the retaining nut.
(4) Connect electrical leads of coil to receptacle. Connect plug of wiring harness to the receptacle on solenoid
valve.
d. Purging the System.
CAUTION
Whenever the refrigeration system has been opened to the atmos-
phere, you must install drier-strainer (dehydrator) before purging
and recharging the system.
When the refrigeration system has been discharged, attach a hose to the gage port of the suction service valve. Connect
a cylinder of oil-pumped dry nitrogen to the gauge port of the high-pressure service valve. Open the high-pressure serv-
ice valve. Crack open the cylinder shutoff valve to establish a flow of 1-2 CFM (0.6 -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.
e. 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:
5-24
