TM 9-4120-404-14
CAUTION
Do not perform the operational check in COOL mode until input power has been
supplied to the unit in accordance with the following:
Ambient (Outside) Temperature
Minimum Input Power Time
60 Degrees F
20 Minutes
40 Degrees F
One (1) Hour
20 Degrees F
Two (2) Hours
Below 20 Degrees F
Four (4) Hours
Liquid refrigerant tends to migrate into the compressor and mix with the lubricating oil.
Since the refrigerant is heavier than the oil, it displaces the lubricating oil from the bottom
of the compressor well. The above sliding timetable for power input to Air Conditioner is
required to boil the liquid refrigerant out of the lubricating oil at the bottom of the
compressor well. This action is needed to prevent "slugging" of the compressor when the
Air Conditioner is started in cool mode and to prevent premature failure of the
compressor.
Before starting the air conditioner in COOL mode, make sure that the fabric condenser
cover on the back of the condenser section is rolled up and secured and that all screens
and guards are in place and unobstructed. This action is needed to avoid damage to the
equipment.
NOTE
Do not adjust controls unnecessarily.
b. General Operation of Controls When the controls are properly set (See paragraphs 2-8 through 2-10.), the
.
unit will automatically control the temperature. The temperature control thermostat on the control panel operates like a
conventional room thermostat except that the temperature scale is not marked on the control panel. The thermostat has a
control range of 60 F to 90F (16C to 32C). The centered position of the control knob would be approximately 75F
(24C). The full WARM would be 90F (32C). The full COOL would be 40F (5C). When the control panel is mounted
in the unit or remotely mounted, the control temperature is always sensed at the conditioned air inlet.
(1) During Cold Weather:
(a) Adjust shades, blinds, etc. (when applicable) to admit sunlight during day. Close them at night.
(b) Adjust the conditioned air outlet louvers slightly downward.
(2) During Hot Weather:
(a) Adjust shades, blinds, etc. (when applicable) to block out sunlight during day.
(b) Adjust the conditioned air outlet louvers slightly upward.
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