TM 9-4120-357-14
(11) Carefully lead sensing bulb and capillary tube to band clamp on suction line between the elbow from the
evaporator coil suction tube extension (4, Figure 4-7) and the tee connection to the equalizer line. Mount sensing bulb 45
degrees below the horizontal centerline of the suction tube, and tighten band clamp. Loop surplus capillary tubing care-
fully to prevent kinking, and secure to equalizer line with tape.
(12) Install a
new drier-strainer (dehydrator) (8, Figure 5-2) with the direction-of-flow arrow pointing down. Con-
nect flare nuts (9), and tighten using a back-up wrench to prevent damaging the connections.
(13) Attach all band clamps (10), loop clamp, spacers ant other attaching hardware to refrigerant tubing and adja-
cent structural members.
(14) Connect capillary tubes from pressure cutout switches to their respective fittings on liquid (high-pressure) ant
suction (low-pressure) lines, if they were disconnected at disassembly. Tighten flare nuts.
(15) Connect a
cylinder of
oil-pumped dry nitrogen to
the compressor discharge service valve. Connect a
hose of
sufficient length to carry exhausted gas to a safe area to the suction line service valve gage port, and open both valves.
Open the nitrogen cylinder shutoff valve slightly to create a flow of 1-2 CFM (0.5 - 1M3) through the system to purge it
while continuing the assembly procedure.
(16) Install evaporator fan, motor and support bracket assembly in
casing, and secure with four cap screws and
washers.
(17) Install the two evaporator fan inlet rings (12 &
13, Figure 4-15) on
the walls of
the return-air plenums, small
diameter facing toward center, and flat of OD facing forward. (See Figure 4-15). Secure with four screws and eight flat
washers in each.
(18) Install heater assembly (Figure 4-14) as a
unit by
lowering the assembly down between the perforated baffle
and the inner surface of the evaporator coil. Secure with two screws through each return air plenum into the bracket
supports (8).
(19) Install wiring harnesses in casing, making sure that grommets are installed in holes to prevent chafing and air
leakage. Secure harnesses to structural members with loop clamps where appropriate.
(20) Install the fresh air grille and baffle assembly (3, Figure 4-6) in
the upper rectangular opening in
the back of
the casing. Secure with 12 screws and washers. Insert the connecting rod (26) into the ball joint (21), and adjust so that
damper (6) is closed when actuating arm (A, 18) is vertical, then tighten locknut on ball joint.
(21) Install the deflector door assembly by securing the hinge support bracket to the casing with six screws. Se-
cure the mounting feet (6, Figure 4-5) of the lid supports (5) to the casing with two screws through each foot.
(22) Slide air filters (2) into slots in back surface of casing, and install covers (1) by tightening six panel fastener
screws in each cover.
(23) 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 tis-
sue damage can result from sudden freezing. Be especially careful to protect the
eyes. Avoid inhaling high concentrations of refrigerant gas, and prevent gas
coming into direct contact with flames or hot metal surfaces; lethal phosgene gas
can be formed.
(a) Connect a cylinder of refrigerant, R22, to the pressure hose. Open the cylinder shutoff valve slightly to
purge the hose of air, then tighten the hose connection to the suction service valve gage port.
(b) Open both service valves and the cylinder shutoff valve, and charge the system with refrigerant 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.
(c) Transfer the charging line to a cylinder of dry nitrogen. Open cylinder shutoff valve and suction service
valve, and let nitrogen flow into the refrigeration system until the discharge pressure gage reads 360 PSI (21.44
KG/CM2). Turn off suction and discharge service valves and cylinder shutoff valve. Disconnect the charging line from
the suction service valve.
6-6