TM 9-4120-411-14
4.4 INSTALLATION INSTRUCTIONS - CONTINUED.
4.4.7.3 Remove filter (3) from flange assembly (4) and install it into NBC adapter (5).
4.4.7.4 Turn flange assembly (4) counterclockwise to unlock then pull it from volute assembly (6).
4.4.7.5 Install the NBC adapter (5) into volute assembly (6). Align slots and turn clockwise to lock in place.
4.4.7.6 Install NBC supply air duct (7) between heater barrel (8) and shelter supply duct connector. Note airflow direction
marked on duct and be sure duct is installed with arrow toward shelter. Tighten two clamps (9) to secure.
NOTE
The NBC return air duct is designed with one duct inside another, sewn together at
one end. This will create an air chamber between the ducts that when pressurized,
4.4.7.7 Install NBC return air duct (10) between NBC adapter (5) and shelter return duct connector. Note airflow direction
marked on duct and be sure duct is installed with arrow toward FDECU. Install the inner duct then tighten clamp (11) to
secure. Install the outer duct then tighten two clamps (12) to secure.
4.4.7.8 Place two NBC filter canisters (13) as illustrated. Be sure they are within three feet of the NBC adapter (5).
4.4.7.9 Place two NBC motor blowers (14) as illustrated. Be sure they are within three feet of their NBC filter canister
(13).
4.4.7.10 Connect and secure one NBC air duct (15) between each NBC motor blower (14) and NBC filter canister (13)
center hole.
4.4.7.11 Connect and secure one NBC air duct (16) between each NBC filter canister (13) outside hole and NBC adapter
(5). Use duct tape to secure hose connections at NBC adapter.
4.4.7.12 Connect one power cord (17) between each NBC motor blower (14) and any two of the three NBC motor blower
power connectors (18) located on the FDECU control box assembly. If several units are being used on the same power
source, be sure not to use the same two connectors on all units as this will unbalance the power supply phases. Try to
use the three connectors equally.
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