1.14 EQUIPMENT CONFIGURATION. The FDECU can be configured for use in either normal environmental conditions
or NBC environmental conditions. Use in NBC environmental conditions requires using the NBC adapter kit and two M-28
Figure 1-4. Equipment Configurations
Section III. PRINCIPLES OF OPERATION
1.15 The FDECU is a horizontally configured electric motor driven heat pump. It has a nominal cooling capacity of
60,000 btu/hr and contains integral resistance heaters. The heaters are used as a supplemental heat source during
system defrost and low ambient temperature conditions. The unit will circulate, filter, provide fresh make-up air, cool and
dehumidify, or heat the air in various types of portable shelters or vans. The unit is designed for use while directly
exposed to the elements and is placed outside the shelter. The unit is connected to the shelter by flexible ducts.
1.16.1 Air from the shelter is drawn in through a flexible duct to the unit. The air then passes over a replaceable filter
then into the inside blower. The air is pushed through the inside coil and the resistance heaters. The air is then pushed
out of the unit through the flexible duct and back into the shelter.
1.16.2 Fresh make-up air is supplied by sliding the flexible duct back on the perforated inside blower inlet collar. This will
expose the perforations and allow outside air to be drawn into the air circulation system.