TM 9-4120-357-14
4-26. Fresh Air Damper Control.
a. General The fresh air damper control adjusts the position of the fresh air damper through a worm and pinion.
(See figure 4-6.) The worm is pinned to the operating shaft which extends through holes in the front and rear surfaces of
the air conditioner casing. The pinion is attached to an actuating arm which opens or closes the fresh air damper through
a connecting rod and ball joint linkage. Except for the knobs at each end of the operating shaft, the entire control is
housed within the air conditioner casing.
b. Inspection. Inspect the control for missing operating knobs, and looseness or binding of the linkage.
c. Removal Remove the fresh air damper control in
accordance with the following directions: (See figure 4-6.)
(1) Loosen setscrews, and remove knobs (9) from both ends of operating shaft (16).
(2) Remove 12 screws and washers from each air intake (return air) grille, and remove the grilles from the front
of the unit.
(3) Remove 12
screws from the top and bottom edges of
the condenser inlet screen (2) and remove the screen
from the back of the unit.
(4) Reach through the front air intake opening, and loosen the binding nut on the ball joint (21) at end of actuator
arm (18, A).
(5) Remove 12 screws and washers from the fresh air intake screen (4) and baffle (5) and lift out the screen and
baffle with damper plate (6) attached.
(6) Remove four screws and self-locking nuts from the corners of the step plate (7) on which the operating
mechanism is mounted.
(7) Move the entire assembly toward the front of the air conditioner until the rear end of the operating shaft (16)
is free of the grommet (10) and hole. Pull the assembly out through the outside air intake opening.
d. Disassembly. Disassemble the fresh air damper control only to the extent necessary to replace damaged parts.
(1) Remove the nut and washer from bolt (15), and withdraw bolt from bracket (8). Remove actuator arm as-
sembly (A). Spacers (23) and spring washers (24).
(2) Drive spring pin (12) out of the worm gear (11), and slide operating shaft (16) out of worm gear and spring
washers (13).
(3) Remove three screws (19) and lock washers (20) from pinion (17) and actuating arm (18).
(4) Remove the self-locking nut from ball joint (21), and remove ball joint from actuator arm (18) or damper plate
(6).
(5) Remove four screws and self-locking nuts fastening bracket (8) to step plate (7).
(6) Remove six screws, washers and nuts from the hinges attaching damper plate (6) to baffle (5).
(7) Loosen screw of ball joint (21), and slide out connecting rod (25).
WARNING
Dry cleaning solvent, P-D-680, used to clean parts, is potentially dangerous to
personnel and property. Avoid repeated and prolonged breathing of vapors and
skin contact with the liquid. Do not use near open flame or excessive heat. Flash
point of solvent is 100 to 138 (38 to 59 ).
F
F
C
C
e. Cleaning and Lubrication. Clean moving parts in dry cleaning solvent (FED SPEC P-D-680), using a soft brush
if necessary to dislodge stubborn accumulations of dirt, dried grease, etc. Clean the intake screen and baffle in detergent
solution. Rinse and blow dry. Apply a thin coating of grease (specification MIL-L-4343) to moving parts during assembly.
Lubricate ball joints and hinges on the damper plate with a light-weight machine oil, (SAE 10 Lubricating Oil) and work in.
Wipe off excess oil.
4-28