TM 9-4120-411-14
4.4 INSTALLATION INSTRUCTIONS - CONTINUED.
4.4.5.4.4 Close power box assembly cover (9) and turn three latches (8) to secure.
4.4.5.4.5 Carefully slide electrical assembly (7) into frame. Be sure no cables or wires are pinched. Secure with eight
captive screws (6).
CAUTION
Ice could form on the inside coil if airflow is restricted. Ducts must be installed as
straight as possible with a minimum number of bends. Unit performance will be
affected and damage to equipment can occur.
4.4.6.1 Install nine foot long supply air duct (1) between heater barrel (2) and shelter supply duct connector. Note airflow
direction marked on duct and be sure duct is installed with arrow toward shelter. Tighten two clamps (3) to secure.
WARNING
Rotating parts are used in operating the FDECU. Do not install or adjust return air
duct when inside blower is operating. The flange assembly can disengage and
come off resulting in personal injury.
NOTE
Fresh outside make-up air is recommended during normal operating conditions.
4.4.6.2 Install seven foot long return air duct (4) between flange assembly (5) and shelter return duct connector. Note
airflow direction marked on duct and be sure duct is installed with arrow toward FDECU. The perforated holes in the
flange assembly are intended to provide from 0 to 500 SCFM of fresh outside air to the shelter depending on how many,
or if any, holes are exposed. Position the duct on the flange assembly as necessary then tighten two clamps (6) to
secure. To assure a continuous supply of fresh makeup air, at least four or five rows of perforated holes should be
exposed. Duct should be fully extended with the least number of bends as possible. Sharp bends, kinks, or collapsed
duct will restrict airflow, lower unit performance, and could cause ice to form on the inside coil.
4.4.6.3 Connect input power cable assembly (7) to a source of 208 Volts AC, 50/60 Hertz, 3-phase, 4-wire plus ground,
16 kilowatt (60 amp). (FDECU-2 ONLY) A compressor crankcase temperature lockout will prevent the compressor from
operating immediately. If the compressor is to operate, power must be connected to the unit for approximately three
hours. This is to raise the compressor temperature above the surrounding ambient air temperature. (FDECU-2 ONLY)
(FOR AIR FORCE ONLY) On
some FDECU-2 units, the compressor crankcase sensor has been bypassed to
eliminate
the compressor warm up delay. This is accomplished by installing a jumper or splice in the harness that will connect the
crankcase sensor (CCS) and common (COM) terminals of terminal block (TP4) on circuit board (A2A1).
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