TM 9-4120-357-14
4-29. Instruction Plates.
Replace damaged or illegible instruction plates by drilling out old rivets and removing the damaged plate. Install a
new instruction plate and secure with blind rivets.
4-30. Drip Pan and Drain Tube.
The drip pan (5, figure 4-7) is located under the evaporator coil (2) and mist eliminator (1). Water condensed from
the water vapor in the air is collected in the drip pan. The water is drained into the base plate of the air conditioner
through tubes (6) at each end of the drip pan. The passage of air through the tubes is prevented by a spring-loaded ball
check valve (7, 8, 9,) at the bottom of the vertical drain tube. Access to the drainage system is obtained by removing the
top panel and all panels and grilles from the front of the unit as follows:
a. Removal of panels. Remove panels as follows:
(1) Remove 16
screws and washers from the frame of
the evaporator discharge grille, and remove the grille.
(2) Remove 22 screws from top, and nine screws from the rear flange of the top panel, and remove the panel.
(3) Remove 12
screws and washers from the frames of
both evaporator intake grilles. Remove grilles.
(4) Slide the mist eliminator up out of guides to remove it.
(5) Unscrew four panel fastener screws from the front access panel. Pull the panel upward and outward to re-
move it.
b. Inspection. Visually inspect the drip pan and drain tubs for obvious damage. Pour water into each end of the
drip pan. Make sure the water flows freely through both the cross-over tube and the vertical tube. If water does not flow
freely, remove the cotterpin, spring and ball from the check valve. Inspect for obstructions by repeating the water-flow
test.
c. Servicing. If water flows freely from the drain pan to the bottom plate through both tubes. No servicing is neces-
sary. If the tubes are blocked, blow out obstruction with compressed air after removing the cotterpin, spring and ball from
check valve.
d. Assembly. Replace the ball (8), spring (9) and cotterpin (7) in the check valve, if removed. Replace panels and
grilles on the air conditioner as follows:
(1) Position the front access panel on the unit by placing the bottom lip behind the step in the base plate. Push
the panel into place and secure it with four captive panel fastener screws.
(2) Slide the mist eliminator (1) into position between the guides; making sure that the top mark faces out.
(3) Position the top panel on the unit, and secure it with 22 screws through the top and nine screws through the
rear flange.
(4) Place the evaporator air discharge grille on
the unit, and secure it
with 16
screws and washers.
(5) Position the evaporator air intake grilles on
the unit, and secure them with 12
screws and washers through the
frame of each grille.
4-33