TM 9-4120-411-14
CHAPTER 2
OPERATING INSTRUCTIONS
Section I. DESCRIPTION AND USE OF OPERATOR'S CONTROLS AND INDICATORS
2.1 DESCRIPTION AND USE OF OPERATOR'S CONTROLS AND INDICATORS. See figure 2-1.
NOTE
The control box assembly and remote box assembly use similar controls and
indicators. The following descriptions will apply to both assemblies with the
exception of the CONTROL SELECTION switch that is only used on the control box
assembly.
2.1.1 The CONTROL SELECTION toggle switch (1) is used to select between the control panel integrated into the
electrical assembly on the unit by placing the switch towards the THIS PANEL position or the remote mounted control
panel that can be placed inside the shelter by placing the switch towards the REMOTE BOX position.
2.1.2 The VENT MODE ON/OFF push button (2) is a momentary switch that, when pushed, will operate the inside blower
to circulate air through the shelter. When pushed again, the unit will shut down. When the unit is operating in the
ventilation mode, the ON indicator (3) will be illuminated.
2.1.3 The CLIMATE CONTROL ON/OFF push button (4) is a momentary switch that, when pushed, will operate the unit
in either heating or cooling mode as necessary to maintain the desired shelter temperature. When pushed again, the unit
will shut down. When the unit is operating in this mode, the ON indicator (5) will be illuminated. Note that a control logic
time-out circuit may prevent the unit from operating immediately. If this occurs, do not turn the unit off, it should start
automatically within 5 minutes.
2.1.4 The TEMPERATURE control knob (6) can be adjusted to select a relative temperature setting to be maintained
o
o
inside the shelter. The knob can be adjusted within a range of 60 F to 100 F. When operating the FDECU, the knob
o
should be set slightly right of the control range mid-point, or 1:00 position, this is approximately 75 F. (Units after
FDECU-2) This position is marked as NORMAL OPERATION.
2.1.5 (FDECU-2 ONLY) The COMPRESSOR WARM UP indicator (7) will be illuminated if the compressor crankcase
heaters are energized. The compressor will not operate until the heaters have cycled off.
2.1.6 Compressors used in the FDECU may or may not contain an oil level indicator. The migration of liquid refrigerant in
and out of the compressor during varying ambient temperatures will cause erratic oil levels to be observed. Do not use
this indicator to determine compressor oil level.
2.1.7 The refrigerant liquid indicator (9) allows for a visual inspection of the liquid refrigerant passing through the system
and is used to aid in diagnosing possible refrigerant system problems. The refrigerant liquid indicator also contains a
colored dot indicator that changes color depending upon the amount of moisture contained in the refrigerant.
Change 1 2-1
